Liquid jet-powered surgical instruments

ABSTRACT

The present invention provides a series of devices useful for surgical procedures utilizing rotatable components for grinding, cutting, ablating, polishing, drilling, screwing, etc., tissues of the body of a patient. The invention includes, in one aspect, a series of devices comprising surgical instruments including rotatable shafts, and surgical components drivable by the shafts that can be utilized for contact with tissue in a surgical operating field. Some preferred surgical instruments provided by the invention utilize a liquid jet-driven rotor mechanism for driving rotation of the rotatable shaft. Some preferred instruments provided by the invention include both a liquid jet-driven rotor mechanism and a nozzle at the distal end of the instrument for forming a liquid cutting jet for cutting or ablating tissue of a patient. Such instruments can include a liquid flow directing valve therein that includes a pressure-tight sealing component comprising a sealing element that is constructed and arranged to be slidably moveable within a cylinder of the valve. The invention provides methods for utilizing the inventive surgical instruments in surgical procedures involving both cutting or ablating tissue of a patient with a liquid cutting jet and grinding, cutting, or ablating tissue with a rotating surface of a surgical instrument.

RELATED APPLICATIONS

[0001] This application is a continuation of U.S. patent applicationSer. No. 10/262,274, filed Oct. 1, 2002, entitled Liquid Jet-PoweredSurgical Instruments by Timothy E. Moutafis et al., which is a divisionof U.S. patent application Ser. No. 09/480,500, filed Jan. 10, 2000,which issued as U.S. Pat. No. 6,511,493 on Jan. 28, 2003, eachincorporated herein by reference.

FIELD OF THE INVENTION

[0002] The invention relates to surgical instruments, more specificallyto surgical instruments providing rotating shafts for performingsurgical functions, and to methods for using the instruments in surgicalprocedures.

BACKGROUND OF THE INVENTION

[0003] Traditionally, many surgical procedures have been performed onpatients using open surgical methods that utilize relatively largeincisions to expose a surgical field. Many traditional methods have alsotypically utilized surgical tools such as scalpels, scrapers, bluntdissectors, lasers, electrosurgical devices, etc., which can have poortissue differentiating capability and which can sometimes causeinadvertent damage to tissue surrounding a surgical treatment siteunless carefully utilized. Open surgery with such prior art surgicalinstruments often involves extensive trauma to the patient, withassociated problems of long recovery periods and potentialcomplications.

[0004] There has been a trend in recent years to perform many surgicalprocedures using less invasive techniques by accessing surgical sitesvia small holes through the skin or through body orifices. Thesetechniques are known as “minimally invasive surgery.” Minimally invasivesurgical techniques commonly employed include endoscopic, laparoscopic,and arthroscopic surgical procedures. Minimally invasive surgicalprocedures are commonly preferred to open surgical procedures for manyapplications because the minimally invasive procedures induce lesstrauma to the patient during surgery and involve, in many cases, fewerpotential complications and reduced recovery time.

[0005] A variety of surgical instruments have been developed andutilized both for minimally invasive surgical procedures and for moretraditional open surgical procedures. Frequently used instrumentsinclude blade and scalpel-type instruments, motorized rotary cuttingand/or grinding instruments, laser instruments, liquid jet cuttinginstruments, and electrosurgical instruments. Typically, prior artinstruments suffer from a variety of disadvantages. For example, typicalprior art surgical instruments, especially those utilized for minimallyinvasive surgical procedures, have distal ends including a singlecomponent for performing a particular surgical function. Surgicalinstruments having distal ends including, for example, a rotatingcutting or grinding head, a tissue-ablating laser, a liquid cutting jet,or an electrosurgical cutting jet are known in the art. Many of theseprior art instruments suffer from a variety of disadvantages. Forexample, instruments having a distal end configured to perform only acutting function must be removed from a surgical field of a patient andreplaced with additional instruments if other surgical functions, suchas grinding or electrocautery, are required. Similarly, instrumentsincluding, for example, a distal end having a grinding component or anelectrosurgical or electrocautery component must be removed from asurgical site and exchanged with additional instrumentation forperforming other functions, such as surgical cutting, etc. Such aremoval and exchange of surgical instruments, especially when performingduring minimally invasive surgical procedures, can be undesirable bothfrom the standpoint of the speed and convenience, and also from thestandpoint of the safety and effectiveness of the surgical instrument inperforming complex surgical procedures requiring multiple tasks to beperformed in the surgical operating field.

[0006] For a variety of surgical procedures, including a variety ofminimally invasive surgical procedures, it is often desirable to utilizea surgical instrument including a rotating component in the surgicalfield. Instruments providing rotating components may be advantageouslyutilized for surgical tasks such as grinding, polishing, drilling,cutting with rotating cutting blades, etc. Typical prior art surgicalinstruments providing rotating shafts for use in surgical procedurestypically have employed electric motors to drive rotation of the shafts,or, alternatively, have employed pneumatically driven rotating turbinerotors. Such prior art instruments suffer from a variety ofdisadvantages. For example, instruments driven by electric motors oftencreate rotation of grinding burrs, or other tissue contacting componentsconnected to the rotating shaft, having relatively poor responsivenessof the rotational speed of the shaft to the resistance and torqueapplied to the tissue contacting component in the surgical field duringoperation. This poor responsiveness and feedback can, in some instances,lead to a variety of difficulties such as difficulty in maintainingcontact of the rotating tissue contacting component, for examplegrinding burr, of the device with tissue in a particular desiredlocation within a surgical field (e.g., due to skating or skipping of agrinding burr along the surface being ground), and also can lead toundesirable transmission of torque to a handle or other user interfaceof the surgical device, potentially causing a lack of operator controland unintended tissue damage.

[0007] Pneumatically powered surgical devices providing rotating shaftstypically provide better compensation of the rotational speed of therotating shaft with applied load than electric motor poweredinstruments; however, pneumatically powered instruments require thatsurgical instruments be coupled to a source of highly pressurized gasduring operation of the instruments, which can be inconvenient,expensive, or undesirable.

[0008] U.S. Pat. No. 5,803,733 to Trott et al. describes a pneumaticallypowered surgical handpiece in which the pressurized fluid inlet isaxially directed relative to the handpiece body. The handpiece includesa reaction-type turbine that is rotated by fluid flowing within a closedconduit. The handpiece utilizes a cantilevered turbine rotor, whereinthe output shaft of the handpiece and the turbine rotor rotate aboutaxes which are co-linear.

[0009] Surgical instruments utilizing liquid-driven turbine rotors arealso known. U.S. Pat. No. 4,631,052 to Kensey describes an elongated,flexible recanalization catheter that includes a working head which isadapted to be rotated by a turbine drive in operation. The turbine driveutilizes a liquid-driven turbine rotor comprising a reaction turbinewhose rotational motion is imparted by pressure driven liquid flowing ina closed conduit. The turbine rotor and the rotating working head of thedevice are directly coupled together so that they rotate at essentiallythe same speed during operation. In addition, the rotor assembly isdisposed at the distal end of the catheter and is essentially completelysubmerged in liquid during operation.

[0010] U.S. Pat. No. 4,690,140 to Mecca describes a catheter for use inthe removal of deposits lining the interior wall of a blood vessel thatincludes a rotating cutting device at its distal end. Rotational motionof the rotating cutting device is imparted by flow of a pressure-drivenliquid. The cutting surfaces of the rotating cutting device and theturbine rotor comprise a single component rotating at essentially thesame speed and about the same rotational axis. As with the '052 patentdescribed above, the rotating cutting element of the '140 patent isdisposed at the distal end of the catheter such that the turbine rotorcausing rotation of the device is essentially completely submerged inliquid during operation.

[0011] Surgical instruments providing electrosurgical cutting orcauterizing electrodes in combination with rotating surgical componentsor liquid perfusion and/or aspiration capabilities are also known.

[0012] U.S. Pat. No. 5,527,331 to Kresch describes a tissue resectiondevice for use in an organ inflated with a non-conductive fluid. Thedistal end of the device can include a perfusion lumen, a rotatabledrive tube, and a drive tube aspiration lumen. A cutting tip can bemounted on the distal end of the drive tube. In some configurations, thecutting tip is further configured to act as an electrosurgical resectionelectrode.

[0013] U.S. Pat. No. 5,941,876 to Nardella et al. describes anelectrosurgical apparatus that includes a rotary, tissue affectingdevice, such as a rotating blade component, a rotating drill, or arotating shaving/ablating device. The rotating device also serves as anactive, energy delivering electrode for electrosurgery.

[0014] U.S. Pat. No. 5,254,117 to Rigby et al. describes amulti-functional endoscopic probe apparatus capable of applying either alow or high frequency voltage to cut and cauterize tissue. The apparatusincludes an elongated multi-lumen tube. The multi-lumen tube includes anirrigation lumen, a suction lumen, and a lumen providing passage for aslidably extendible and retractable electrosurgical cutting tip. Theinner and outer surfaces of the multi-lumen tube can be coated with alayer of polyamide of uniform thickness for insulation. In someembodiments, the outer surface of the multi-lumen tube is further coatedwith a shrink-wrapped polytetrafluoroethylene insulating layer.

[0015] U.S. Pat. No. 5,429,596 to Arias et al. describes an endoscopicelectrosurgical suction-irrigation instrument with insertable probes andattachments. The instrument includes a fluid chamber that is sealed atits proximal end, includes slit valve for receiving the probes, and isconnected at its distal end to a cannula through which the insertedprobes extend. The fluid chamber can be selectively provided withsuction and/or irrigation and includes an electrical contact forsupplying voltage to an inserted electrosurgical probe. Depending on theprobe configuration, suction and/or irrigation can be provided in anannular space between the probe and the cannula or through the probe.

[0016] International Patent Application No. WO 97/24074 having inventorsIsaacson et al. describes a hysteroscopic electrosurgical device. Thedevice includes an electrosurgical probe, an irrigation channel, and anevacuation channel. In some configurations, a return electrode of thebipolar system provided by the instrument extends along an inner and/orouter surface of a sheath that is concentric about the positiveelectrode assembly.

[0017] While the above mentioned surgical instruments represent, in someinstances, improvements over many prior art surgical instruments forperforming open and minimally invasive surgical procedures, thereremains a need in the art to provide surgical instruments which haveimproved cutting, ablation, grinding, and/or tissue cauterizingcapabilities, and which also have the ability to be utilized in a widevariety of open and/or minimally invasive surgical procedures to performa variety of surgical functions. The present invention provides, in manyembodiments, such improved surgical instruments, and further providesmethods for their use in a variety of surgical procedures.

SUMMARY OF THE INVENTION

[0018] The present invention provides a series of devices useful forsurgical procedures utilizing rotatable components for grinding,cutting, ablating, polishing, drilling, screwing, etc., tissues of thebody of a patient. The invention includes, in one aspect, a series ofdevices comprising surgical instruments including rotatable shafts, andsurgical components drivable by the shafts that are constructed andarranged for contact with tissue in a surgical operating field. Inanother aspect, the invention provides a pressure-tight sealingcomponent comprising an element constructed and arranged to be slidablymoveable within a cylinder and, in yet another aspect, the inventionprovides a method for utilizing the inventive surgical instruments.

[0019] In one aspect, a series of devices comprising surgicalinstruments are described. One device comprises a surgical instrumenthaving a distal end adapted to perform a surgical procedure on a patientand a proximal end adapted to be controllable by an operator. Theinstrument includes a rotatable shaft. The instrument further includes asurgical component that is drivable by the shaft and constructed andarranged for contact with a tissue in a surgical operating field. Theinstrument further includes a liquid jet-driven rotatable rotor. Therotor is drivingly coupled to the rotatable shaft, when the instrumentis in operation, such that the rotation of the liquid jet-drivenrotatable rotor causes a corresponding rotation of the rotatable shaft.Furthermore, the liquid jet-driven rotatable rotor is maintained in asurrounding gaseous environment while being rotatably driven by at leastone liquid jet during operation, so that essentially no part of therotor is submerged in liquid.

[0020] Another device comprises a surgical instrument having a distalend adapted to perform a surgical procedure on a patient and a proximalend adapted to be controllable by an operator. The instrument includes apressure lumen having sufficient burst strength to conduct a highpressure liquid towards the distal end of the instrument. The pressurelumen includes at least one nozzle providing a jet opening. The nozzleis shaped to form a liquid cutting jet as a liquid at high pressureflows therethrough. The instrument further includes a rotatable shaftand a surgical component that is drivable by the shaft and isconstructed and arranged for contact with tissue in a surgical operatingfield.

[0021] Yet another device comprises a surgical instrument having adistal end adapted to perform a surgical procedure on a patient and aproximal end adapted to be controllable by an operator. The instrumentincludes a rotatable shaft and a surgical component that is drivable bythe shaft and constructed and arranged for contact with tissue in asurgical operating field. The instrument further includes a rotatablerotor that is drivingly coupled to the rotatable shaft, when theinstrument is in operation, such that rotation of the rotatable rotorcauses a corresponding rotation of the rotatable shaft. The instrumentfurther includes a pressure lumen having a proximal end, and a distalend. The pressure lumen has a sufficient burst strength to conduct ahigh pressure liquid. The distal end of the pressure lumen includes anozzle therein that is shaped to form a liquid jet as a liquid at highpressure flows therethrough. The nozzle is positioned so that at least aportion of the liquid jet emanating therefrom impacts a surface of arotatable rotor, thereby imparting rotational motion to the rotor, suchthat there is essentially no change in hydrostatic pressure of theliquid comprising the liquid jet while in contact with the rotor.

[0022] Another device comprises a surgical instrument having a distalend adapted to perform a surgical procedure on a patient and a proximalend adapted to be controllable by an operator. The instrument includes arotatable shaft having a longitudinal axis defining an axis of rotationof the shaft. The instrument also includes a surgical component that isdrivable by the shaft and is constructed and arranged for contact withtissue in a surgical operating field. The instrument further includes aliquid jet-driven rotatable rotor. The rotor is drivingly coupled to therotatable shaft, when the instrument is in operation, such that rotationof the liquid jet-driven rotatable rotor causes a corresponding rotationof the rotatable shaft. The rotatable rotor is configured to rotateabout an axis of rotation that is essentially perpendicular to the axisof rotation of the rotatable shaft.

[0023] Yet another device comprises a surgical instrument having adistal end adapted to perform a surgical procedure on a patient and aproximal end adapted to be controllable by an operator. The instrumentincludes a rotatable shaft having a longitudinal axis defining an axisof rotation of the shaft. The instrument also includes a surgicalcomponent that is drivable by the shaft and is constructed and arrangedfor contact with tissue in a surgical operating field. The instrumentfurther includes a liquid jet-driven rotatable rotor, drivingly coupledto the rotatable shaft, when the instrument is in operation, such thatrotation of the liquid jet-driven rotatable rotor causes a correspondingrotation of the rotatable shaft. The rotatable rotor is configured torotate about an axis of rotation at a first rotational speed, and therotatable shaft rotates about the longitudinal axis defining an axis ofrotation of the shaft at a second rotational speed that is differentfrom the first rotational speed.

[0024] Another device comprises a surgical instrument having a distalend adapted to perform a surgical procedure on a patient and a proximalend adapted to be controllable by an operator. The instrument includes arotatable shaft and a surgical component that is drivable by the shaftand is constructed and arranged for contact with tissue in a surgicaloperating field. The instrument further includes a liquid jet-drivenrotatable saw-tooth rotor. The saw-tooth rotor is drivingly coupled tothe rotatable shaft, when the instrument is in operation, such thatrotation of the liquid jet-driven rotatable saw-tooth rotor causes acorresponding rotation of the rotatable shaft.

[0025] In another aspect, a method for performing a surgical procedureis disclosed. The method comprises inserting a surgical instrument intoa surgical field of a patient, creating a liquid cutting jet with thesurgical instrument, cutting or ablating a first selected tissue of thepatient with the liquid cutting jet, rotating a rotatable component ofthe surgical instrument, contacting a rotating surface of the rotatablecomponent with a second selected tissue, and grinding, cutting, orablating the second selected tissue with the rotating surface.

[0026] In yet another aspect, a pressure-tight sealing component isdescribed. The pressure-tight sealing component comprises an elementthat is constructed and arranged to be slidably moveable within acylinder. The element is positionable on a shaft within the cylindersuch that the element moves within the cylinder upon motion of theshaft. The element is shaped to include an integral, flared sealingflange portion that is constructed and arranged to make sealing contactwith an internal surface of the cylinder while preventing contact bothbetween the cylinder and the shaft, and between the cylinder and anyother portion of the element. The flared sealing flange portion of theelement when in contact with the internal surface of the cylinder,provides a leak-tight seal at the point of contact between the flaredsealing flange portion of the element and the internal surface of thecylinder. This seal is able to withstand a differential in pressure ofat least 1,000 psi without leakage of fluid therethrough.

[0027] Other advantages, novel features, and objects of the inventionwill become apparent from the following detailed description of theinvention when considered in conjunction with the accompanying drawings,which are schematic and which are not intended to be drawn to scale. Inthe figures, each identical or nearly identical component that isillustrated in various figures is represented by a single numeral. Forpurposes of clarity, not every component is labeled in every figure, noris every component of each embodiment of the invention shown whereillustration is not necessary to allow those of ordinary skill in theart to understand the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028]FIG. 1 is a schematic, perspective illustration of a surgicalliquid jet instrument providing a liquid cutting jet and a rotating burrat its distal end, with the body of the instrument disassembled to showthe internal components thereof;

[0029]FIG. 2A is a schematic, exploded, perspective illustration of aportion of the surgical instrument as in FIG. 1 showing the sheath andcollar and components contained therein;

[0030]FIG. 2B is a schematic, cross-sectional illustration of the distalend of the surgical instrument as in FIG. 2A showing the distal end ofthe rotatable shaft and the support element therefor;

[0031]FIG. 2C is a schematic, cross-sectional illustration of therotatable shaft and support element of the instrument as in FIG. 2B;

[0032]FIG. 3 is a schematic, perspective illustration of the surgicalinstrument as in FIG. 1, excluding the body of the instrument, and asviewed from the proximal end of the instrument;

[0033]FIG. 4 is a schematic, partially-cutaway, perspective illustrationof the surgical instrument as in FIG. 1, wherein the sheath componenthas been rendered transparent;

[0034]FIG. 5A is a schematic, perspective illustration of a portion of asurgical instrument showing an alternative embodiment for providing adistal end including a liquid cutting jet and a rotatable grinding burr;

[0035]FIG. 5B is a schematic, perspective illustration of a portion of asurgical instrument showing another alternative embodiment for providinga distal end of a surgical instrument providing both a liquid cuttingjet and a rotatable grinding burr;

[0036]FIG. 6A is a partially-cutaway, schematic illustration of aportion of the distal end of a surgical liquid jet instrument forcreating a liquid cutting jet in a surrounding liquid environment;

[0037]FIG. 6B is partially-cutaway, schematic illustration of a portionof the distal end of a surgical liquid jet instrument for creating aliquid cutting jet in a liquid environment, where the evacuation lumenincludes a constriction;

[0038]FIG. 6C is a schematic illustration of a portion of the distal endof a surgical liquid jet instrument, illustrating various geometricrelationships;

[0039]FIG. 7A is a schematic, perspective illustration of a portion of arotatable shaft including a grinding burr at its distal end, where therotatable shaft includes a helically grooved channel disposed on atleast a portion of the outer surface of the shaft;

[0040]FIG. 7B is a schematic, perspective illustration of a portion of arotatable shaft including a grinding burr, where the rotatable shaftincludes an impeller thereon;

[0041]FIG. 7C is a schematic, perspective illustration of a portion of arotatable shaft with a grinding burr thereon and including a scoopshaped aperture in fluid communication with a channel defined by ahollow center of the shaft;

[0042]FIG. 8A is a schematic, exploded, perspective illustration of therotatable shaft drive mechanism of the instrument as in FIG. 1;

[0043]FIG. 8B is a schematic, perspective illustration of a rotorassembly and rotatable shaft drive assembly of the rotatable shaft drivemechanism as in FIG. 8A;

[0044]FIG. 8C is a partially-cutaway, schematic illustration of aportion of the rotatable shaft drive mechanism as in FIG. 8A showing thearrangement of the liquid jet nozzle, rotatable rotor, and liquid jetevacuation lumen;

[0045]FIG. 8D is a schematic illustration of the liquid jet evacuationlumen and rotor assembly as in FIG. 8C, as viewed from above;

[0046]FIG. 8E is a schematic, perspective illustration of a portion ofthe evacuation lumen as in FIG. 8D;

[0047]FIG. 9A is a schematic illustration of a saw-tooth rotor;

[0048]FIG. 9B is a schematic illustration of a portion of the saw-toothrotor as in FIG. 9A, as viewed from above;

[0049]FIG. 10A is a schematic, perspective illustration of a curved-veinrotor;

[0050]FIG. 10B is a schematic illustration of several curved veins ofthe curved-veined rotor as in FIG. 10A;

[0051]FIG. 11A is a schematic illustration of one embodiment of aconfiguration for providing evacuation for a surgical instrument;

[0052]FIG. 11B is a schematic illustration of another embodiment forproviding evacuation for a surgical instrument;

[0053]FIG. 12 is a schematic, cross-sectional illustration of the liquidflow directing valve of the instrument as in FIG. 1;

[0054]FIG. 13 is a schematic, cross-sectional illustration of thepressure-tight sealing component and spacer component of the liquid flowdirecting valve as in FIG. 12;

[0055]FIG. 14A is a schematic illustration of a rotatably deployablesurgical liquid jet instrument including integrated electrocauteryelectrodes;

[0056]FIG. 14B is a schematic illustration of a portion of the surgicalliquid jet instrument as in FIG. 14A showing more clearly the distal endof the instrument, when in the undeployed configuration;

[0057]FIG. 14C is a schematic illustration of a portion of the liquidjet instrument as in FIG. 14A showing more clearly the distal end of theinstrument, when in the deployed configuration;

[0058]FIG. 14D is a partially-cutaway, schematic illustration of aportion of the surgical liquid jet instrument as in FIG. 14A;

[0059]FIG. 14E is a partially-cutaway, schematic illustration of aportion of the surgical liquid jet instrument as in FIG. 14A;

[0060]FIG. 14F is a schematic illustration of the actuating element ofthe surgical liquid jet instrument as in FIG. 14A;

[0061]FIG. 15 is a series of schematic illustrations illustrating amethod for forming a liquid jet nozzle region;

[0062]FIG. 16A is a schematic, perspective illustration of a surgicalinstrument as in FIG. 1, but including integrated electrocauteryelectrodes; and

[0063]FIG. 16B is a schematic, perspective illustration of a portion ofthe surgical instrument as in FIG. 16A, showing the configuration of thedistal end of the instrument.

DETAILED DESCRIPTION

[0064] The present invention provides a variety of liquid jetinstruments useful in a variety of applications, many of whichinstruments are especially well suited for performing a variety ofsurgical procedures. The liquid jet instruments provided by theinvention can be configured in a variety of different was for use invarious surgical operating fields. Furthermore, the liquid jets createdby the instruments can be used for a wide variety of purposes; forexample, as liquid cutting jets to cut, ablate, sculpt, debride,delaminate, etc. various tissues of a human or animal body. The term“tissue” as used herein refers broadly to a component of a human oranimal body, such components including but not limited to muscle, skin,cartilage, tendon, bone, tooth, brain, cardiac tissue, vessels, internalorgans, tissue of the eye, etc.

[0065] The liquid jets may also be used to provide driving power torotate rotatable shafts provided by instruments according to certainembodiments of the invention. The rotatable shafts of such instrumentscan be used for performing various surgical tasks, such as grinding,abrading, cutting, drilling, polishing, screwing, powering fasteningtools, etc.

[0066] Certain preferred surgical instruments, provided according to theinvention, are configured as surgical handpieces having a proximal endwith a grasping region, or body, shaped and configured to be comfortablyheld in the hand of an operator. The instruments also have a distal endthat includes at least one component constructed and arranged forcontact with tissue. As discussed in more detail below, in certainembodiments, the above-mentioned component can comprise the distal endof a rotatable shaft, which may include, for example, a grinding burr, acutting blade, a drill, a screwdriver, or other component.

[0067] In certain preferred embodiments, the instruments have a distalend that includes at least one nozzle for forming a liquid cutting jet.The distal end of the various inventive surgical instruments can beutilized, in certain preferred embodiments, to perform a surgicalprocedure on a patient. Although the surgical instruments describedherein are shown as having a handpiece configuration, it should beunderstood that the invention is not strictly limited to surgicalhandpieces, and that the invention may also be practiced utilizinginstruments including at least one liquid jet forming component buthaving a variety of alternative configurations and purposes. Forexample, instead of being configured as a surgical handpiece, theinventive surgical instruments could be configured for manipulation bymachine control, such as a X/Y/Z positioning machine. Also, forembodiments involving instruments providing a liquid cutting jet at thedistal end of the instrument, the liquid jet instrument can be used in awide variety of surgical applications and utilize the high pressureliquid cutting jet to cut, drill, bore, perforate, strip, delaminate,liquefy, ablate, shape, form, etc. various tissues, organs, etc. of thebody of a patient.

[0068] The liquid jet surgical instruments provided by the inventionpreferably include at least one pressure lumen that has a distal endterminating in at least one nozzle that provides a liquid jet opening,and that has a proximal end that is connectable so as to be in fluidcommunication with a source of liquid under high pressure, supplied, forexample, by a high pressure pump or high pressure liquid dispenser. Theliquid jet nozzle is shaped to form a liquid jet as a liquid under highpressure flows through the nozzle as described in greater detail below.The liquid jet, in certain embodiments, is used to create a drivingforce for rotating a rotatable shaft of the instrument that can extend,in preferred embodiments, from the body of the surgical instrumenttowards the distal end of the instrument. In some embodiments, theinstrument includes a pressure lumen that conducts a high pressureliquid toward the distal end of the instrument and that includes atleast one nozzle that creates a liquid cutting jet as a high pressureliquid flows therethrough. The liquid cutting jet, for embodimentswherein the surgical instrument provides a liquid cutting jet at itsdistal end, can be used to cut, ablate, sculpt, trim, form, debride,etc., various tissues of a patient in surgical procedures.

[0069] In some especially preferred embodiments, the surgicalinstruments provided by the invention include two pressure lumen, onefor forming a liquid cutting jet at the distal end of the instrument andthe other for forming at least one liquid jet utilized to drive therotation of a rotatable shaft included in the surgical instrument. Insome preferred embodiments, the liquid pressure supplied to theinstrument by a high pressure pump or high pressure dispenser can bevariably controllable by an operator of the instrument so that thecutting or ablating power of the liquid cutting jet, or the powersupplied to rotate the rotatable shaft, is adjustable by the operator.This adjustability of the pressure can allow an operator to create aliquid cutting jet with the instrument that can differentiate betweendifferent types of tissue within a surgical operating field and/or canallow an operator to rotate a rotatable shaft of the instrument atvarying rotational speeds with varying maximum achievable levels oftorque according to the particular needs of the surgical procedure forwhich the distal end of the rotating shaft is being utilized.

[0070] For example, for embodiments including a liquid cutting jetprovided at the distal end of the instrument, a lower pressure can beutilized for cutting or ablating a soft tissue, such as fat, from asurface of a harder tissue, such as muscle or bone, where the liquid jethas sufficient strength to cut or ablate the soft tissue withoutdamaging the underlying harder tissue. A higher pressure can then beselected that is sufficient to form a liquid cutting jet capable ofcutting or ablating hard tissue, such as muscle or bone. For embodimentsincluding liquid jet-driven rotatable shafts, a relatively low pressureliquid can be utilized for embodiments wherein a relatively lowrotational speed and/or low torque is required, for example forembodiments having a cutting blade disposed at the distal end of therotatable shaft that is used for cutting or trimming relatively softtissue, and a high pressure liquid may be utilized for surgicalprocedures where higher rotational speeds and/or maximum torques arerequired, for example for embodiments where a grinding burr comprises,or is connectable to, the distal end of the rotatable shaft and is used,for example, for grinding hard tissue such as bone. In this way, theliquid jet surgical instruments provided by the invention, can, in manyembodiments, provide highly selective and controllable tissue cutting,ablating, grinding, etc., in various surgical procedures. In addition,as discussed in more detail below, for embodiments involving surgicalinstruments providing both a liquid cutting jet and a rotatable shaftfor performing surgical procedures, a liquid flow directing valve may beincluded within the body of the surgical instrument. The valve canfunction to direct a high pressure liquid to the pressure lumen withinthe surgical instrument that is in fluid communication with the liquidcutting jet forming nozzle at the distal end of the instrument, to thepressure lumen that is in fluid communication with the nozzle forming aliquid jet configured to drive rotation of the rotatable shaft, or toboth simultaneously.

[0071] Preferred embodiments of the inventive surgical instruments thatare configured to provide a liquid cutting jet at their distal end alsoinclude a liquid jet target or dissipater that is locatable opposite thejet opening orifice in the nozzle from which the liquid cutting jet isemitted (hereinafter referred to the “liquid jet opening” or “jetopening”) at a predetermined distance from the liquid jet opening inorder to receive and/or dissipate energy of a liquid cutting jet, whenthe instrument is in operation. Embodiments including a target ordissipater are preferred because the target/dissipater prevents theliquid cutting jet from being misdirected during use and potentiallycausing damage to unintended tissue sites in the surgical operatingfield. The target/dissipater enables the instrument to provide apredetermined liquid cutting jet length defined by the predetermineddistance between the liquid jet opening in the nozzle and the surface ofthe target/dissipater upon which the cutting jet impinges. With suchembodiments, the liquid cutting jet can be utilized for performingsurgical cutting or ablating of tissue with a reduced danger of causingunintended collateral damage to tissue lying beyond thetarget/dissipater in the surgical operating field.

[0072] In some embodiments, the target/dissipater can be simply a solidsurface capable of dissipating the energy of a liquid cutting jet bytransforming the liquid jet into a harmless spray. In more preferredembodiments, however, the target is defined by a jet-receiving openingincluded in an evacuation lumen that forms part of the surgicalinstrument. In the preferred embodiments of instruments including anevacuation lumen having a jet-receiving opening, in addition toproviding a defined liquid jet length (defined by the predetermineddistance between the liquid jet opening and the jet-receiving opening)and preventing unintended damage as discussed above, the evacuationlumen can also be utilized for removing liquid, ablated tissue, anddebris from the surgical field. In some embodiments of surgical jetinstruments having an evacuation lumen for receiving a liquid cuttingjet according to the invention, an external source of suction, forexample a vacuum pump or aspirator, can be provided in fluidcommunication with a proximal end of the evacuation lumen in order toprovide the suction driving force required for evacuating material fromthe surgical field via the jet-receiving opening. In some preferredembodiments, however, the invention provides surgical instruments havingan evacuation lumen that is shaped and positionable relative to the jetnozzle forming the liquid cutting jet (as will become apparent to thoseof ordinary skill in the art from the detailed description below) toenable evacuation of essentially all of the liquid comprising the liquidcutting jet as well as ablated tissue and debris from the surgical sitewithout requiring an external source of suction. In some preferredembodiments, the evacuating force created by the liquid cutting jetbeing directed into the evacuation lumen is sufficient to evacuatematerial from the operating site to a drainage reservoir located at theproximal end of the evacuation lumen or an evacuation conduit connectedto the proximal end of the evacuation lumen. In such embodiments, theliquid cutting jet and the evacuation lumen together act as an eductorpump, which utilizes the momentum and kinetic energy of the moving fluidof the liquid cutting jet to create an evacuating force capable ofdriving liquid, ablated material, and debris through the evacuationlumen and away from the surgical site.

[0073] As discussed in detail below, the invention teaches that theeffectiveness of evacuation of material through the evacuation lumenwithout the use of an external source of suction (i.e., via eductor pumpaction) can be improved, in some instances, by designing certaininventive instruments to provide particular geometrical relationshipsbetween the components for forming the liquid cutting jet and thecomponents for receiving the liquid cutting jet, relating, for example,the size of the jet-receiving opening in the evacuation lumen to thepredetermined distance between the jet-receiving opening and the jetopening for forming the liquid cutting jet with the nozzle. Also, astaught by the invention, interrelated with the above-mentionedgeometrical relationships for providing effective eductor pump action isthe design of the liquid jet nozzle and the shape of the jet-receivingopening in the distal end of the evacuation lumen.

[0074] The liquid jet surgical instruments provided according to theinvention may be utilized for performing surgical procedures, involvingliquid cutting jets and/or rotatable tissue contacting surgicalcomponents, in a wide variety of surgical fields, including thosecomprising both liquid-filled and gaseous environments. As describedbelow, certain of the inventive surgical instruments providing liquidcutting jets at their distal ends are especially well suited forperforming surgical procedures in a liquid-filled surgical environment,where the distal end of the instrument, including, in some embodiments,the nozzle for forming the liquid cutting jet and the jet-receivingopening, are submerged in a liquid when the instrument is in operation.Such devices can be configured as surgical handpieces for use, forexample, in endoscopic, arthroscopic, or other surgical procedures.

[0075] As is described herein, and in much greater detail in commonlyowned co-pending U.S. patent application Ser. No. 09/313,679, entitledFLUID JET SURGICAL INSTRUMENTS, incorporated herein by reference, theinventive surgical liquid jet instruments that provide a liquid cuttingjet at their distal end, can be configured to effectively removematerial from the surgical site and transport the material through anevacuation lumen without the need for an external source of suction fora wide variety of angular orientations between the central region of theliquid cutting jet and the longitudinal axis of the evacuation lumen.The term “central region of the liquid jet” as used herein refers to aregion defining a geometric center of the liquid jet. This region istypically an essentially cylindrical region of the liquid jet confinedwithin a cylinder whose outer surfaces are shaped and whose perimeter isdefined by the inner circumference of the liquid jet opening in thenozzle, which circumference is projected from the liquid jet opening tothe jet-receiving opening along an axis that is co-linear with thelongitudinal axis of the jet nozzle. The “longitudinal axis” of the jetnozzle, as will be described in more detail below, is defined by theaxial center line of the nozzle region of the pressure lumen. The“longitudinal axis” of the evacuation lumen refers to an axis definingthe geometric center of the evacuation lumen in a region that isproximal to the jet-receiving opening. As used herein in the context ofdescribing geometric relationships between longitudinal axes of variouscomponents, the term “co-linear” refers to components whose longitudinalaxes are superimposed on essentially the same line and space. The term“parallel” when used in the same context refers to longitudinal axesthat are not necessarily co-linear, but that are oriented in anessentially identical direction in space. Accordingly, surgicalinstruments provided according to certain embodiments of the inventionenable effective evacuation of material and debris from the surgicalsite via a liquid cutting jet evacuation lumen, without the need for anexternal source of vacuum connected in fluid communication with suchlumen, for a wide variety of liquid cutting jet angular configurations,including instruments providing liquid cutting jets that are directedaxially, transversely, or at any angle between 0 and 180° with respectto a longitudinal axis defining the proximal end or body of the surgicalinstrument.

[0076] For embodiments involving surgical instruments including anevacuation lumen for receiving a liquid cutting jet, plugging of theevacuation lumen can be prevented by constructing the evacuation lumenreceiving the liquid cutting jet to have a region that is within and/ordownstream of the jet-receiving opening that is designed to be able tomacerate at least a portion of the tissue trained by the liquid jet intoa plurality of particles when the instrument is in operation. The term“macerate” as used herein refers to a disaggregation of entrainedmaterial, for example an entrained tissue, by a liquid within theevacuation lumen undergoing intensely turbulent flow that creates aregion of extremely high fluid shear and impacting forces capable ofpartitioning the material into particles having a size small enough topass through the evacuation lumen without plugging the lumen. Inpreferred embodiments, the evacuation lumen is able to macerate asubstantial fraction of the tissue entrained into a plurality ofessentially microscopic particles. “Microscopic” as used herein refersto particles having a dimension too small to be visualized unaided bythe human eye.

[0077] Prevention of blow-by (defined as a portion of a liquid cuttingjet or high velocity fluid entrained by the liquid cutting jet having across-sectional area, at the plane of the jet-receiving opening, that islarger than the cross-sectional area of the jet-receiving opening sothat at least a portion of the liquid cutting jet or high velocity fluidmisses or “blows by” the jet-receiving opening) can be accomplished byproviding a surgical jet instrument having a distal end configured sothat, when in operation, the liquid cutting jet and the high velocityfluid entrained by the liquid cutting jet occupies a substantialfraction of the cross-sectional area of the jet-receiving opening, butdoes not occupy a region larger than the cross-sectional area of thejet-receiving opening. As discussed in more detail below, this“substantial fraction” refers to at least 50%, but less than 100% of thecross-sectional area of the jet-receiving opening being occupied by anentrainment region created by the liquid cutting jet.

[0078] As discussed above, certain embodiments of the surgicalinstruments provided according to the invention include a rotatableshaft, which, in some preferred embodiments, extends from the body ofthe instrument, or from the proximal end of the instrument, towards thedistal end of the instrument. The rotatable shafts provided according tothe invention can have distal ends comprising, or reversibly connectableto, a surgical component that is constructed and arranged for contactwith tissue in a surgical operating field. The “distal end” of therotating shaft as used herein refers to a portion of the rotating shaftlocated at the distal end of the instrument and within a surgicaloperating field when the instrument is in operation. It should beemphasized that the distal end of the rotatable shaft can include, insome embodiments, regions proximal to the extreme distal tip of therotatable shaft that are still within the surgical operating field whenthe instrument is in operation.

[0079] Components constructed and arranged for contact with tissue canbe components that are comprised by the distal end of the rotatableshaft itself or, alternatively, can be components that are removablyattachable/connectable to the distal end of the rotatable shaft. Suchcomponents may, as apparent to those of ordinary skill in the art, beprovided in a wide variety of forms for performing a wide variety offunctions useful in various surgical procedures. For example, in someembodiments, the component can be constructed and arranged to cut,grind, ablate, shape, drill, bore, pulverize, polish, liquefy, screw,etc., a tissue within the operating field. In addition, as described inmore detail below, the rotatable shaft can be permanently, orsemi-permanently, contained within the surgical instrument or,alternatively and more preferably, can be configured to be removable andexchangeable with other rotatable shafts, for example those havingdifferent components at their distal ends for performing differentsurgical functions. It is also contemplated that the rotatable shaft canbe configured within the surgical instrument so that its distal end,including the component constructed and arranged for contact withtissue, is selectively retractable so that, under control of anoperator, the distal end of the rotatable shaft may be selectivelydeployed into the surgical operating field for performing a surgicalprocedure and, when the procedure is completed, retracted into theinstrument and away from the surgical field. Such a retractableconfiguration can be especially useful for instruments including both arotatable shaft and a liquid cutting jet at the distal end of theinstrument, wherein during a surgical procedure requiring the rotatableshaft, the shaft may be deployed into the surgical operating field, butduring a procedure requiring use of only the liquid cutting jet, therotatable shaft may be withdrawn from the surgical field, if desired.

[0080] For instruments provided according to the invention including arotatable shaft therein, the proximal end of the rotatable shaft istypically disposed within a body or at a user-controllable proximal endof the instrument. The proximal end of the shaft is drivingly coupled toa mechanism that is constructed and arranged to impart a rotating motionto the rotatable shaft. The term “drivingly coupled” as used hereinrefers to the shaft being interconnected with a drive mechanism suchthat motion of a component of the drive mechanism imparts rotationalmotion to the rotatable shaft. Such coupling can be accomplished, aswould be apparent to those of ordinary skill in the art, by a variety ofmeans such as, but not limited to, gear drives, belt drives, chaindrives, friction drives, etc. The drive mechanism utilized to rotate therotatable shaft within the instrument can comprise one or more of avariety of drive mechanisms including, but not limited to, electricmotors, pneumatic turbines, etc., as apparent to those of ordinary skillin the art. However, in preferred embodiments, the invention utilizes aninventive liquid jet-driven rotatable rotor, preferably positionedwithin the body or at the proximal end of the instrument, to impartrotational motion to the rotatable shaft.

[0081] Preferred embodiments of the liquid jet-driven rotatable rotormechanism provided according to the invention utilize a pressure lumen,having a liquid jet forming nozzle at a distal end thereof, to direct aliquid jet so that it impacts an impacting surface on the rotatablerotor, thus driving rotation of the rotor, which, in turn, creates acorresponding rotation of the rotatable shaft that is drivingly coupledthereto. Unlike typical prior art fluid driven turbine mechanisms, thepreferred shaft-drive mechanism provided according to the invention doesnot utilize an expanding gas or, as is the case with typical prior artliquid-driven turbines, confine the rotor and liquid flow path within inan enclosed duct or channel such that the rotor is essentiallycompletely submerged in a liquid during its rotation. In such typicalprior art “reaction” turbines, the liquid driving the rotor undergoes asubstantial change in hydrostatic pressure while in contact with thedriving surface of the rotor. In contrast, the liquid jet-drivenrotatable rotor mechanism provided according to the invention preferablymaintains the liquid jet-driven rotor within a surrounding gaseousenvironment while it is being rotatably driven by a liquid jet duringoperation, so that essentially no part of the rotor is submerged inliquid during operation. In other words, the liquid that is in contactwith the rotatable rotor, according to the invention, is essentiallylimited to a region of the liquid jet contacting a jet impacting surfaceof the rotatable rotor. As described in more detail below, the mechanismfunctions by directing an essentially collimated liquid jet, from a jetopening in the nozzle of the pressure lumen, across a gas filled gap sothat it impacts a surface of the rotor, imparting rotational motionthereto. While in the embodiments illustrated below a single liquid jetis directed so that it impacts an impacting surface on a rotatablerotor, thus driving rotation of the rotor, in other embodiments,multiple nozzles in the pressure lumen and/or multiple pressure lumenmay be utilized to direct multiple liquid jets at one or more impactingsurfaces of a single or multiple rotatable rotors within the instrumentfor driving the rotatable shaft, or, alternatively, for driving multiplerotatable shafts.

[0082] In some preferred embodiments, the rotatable rotor is containedwithin a housing within the body of the instrument, which housing isevacuated to remove any accumulated liquid therein so that the rotatablerotor remains essentially unsubmerged in a surrounding liquid duringoperation. In especially preferred embodiments, described in more detailbelow, an evacuation lumen including a jet-receiving opening therein ispositioned opposite the jet opening in the nozzle of the rotor-drivingpressure lumen and downstream of the impacting surface of the rotatablerotor so that it receives and evacuates the liquid comprising therotor-driving liquid jet. Similarly to the evacuation lumen utilized forreceiving and evacuating liquid cutting jets described above, theevacuation lumen utilized for receiving and evacuating the rotor-drivingliquid jet can, in some embodiments, be placed in fluid communicationwith an external source of suction or can, in more preferredembodiments, be configured to enable evacuation of essentially all ofthe liquid comprising the liquid rotor-driving jet without the need foran external source of suction connected thereto. Except as specificallydescribed below, the configurations useful for the nozzle and evacuationlumen utilized in the inventive rotor-driving mechanism can be similarto those described below for forming and evacuating a liquid cuttingjet.

[0083] The preferred liquid jet-driven rotatable rotor described aboveutilizes primarily the impulse force resulting from a change in themomentum of the liquid jet, upon contact with an impacting surface ofthe rotor, to impart rotational motion to the rotor. In the inventiveconfiguration, liquid leaves the nozzle of the pressure lumen as a jethaving a free-surface, at the jet opening, in the surrounding gaseousenvironment. In such configuration, essentially the entire pressure dropof the liquid comprising the jet to atmospheric pressure takes placewithin the nozzle. By contrast, typical prior art fluid-driven drivemechanisms for use in surgical devices employ a turbine-driving fluidstream that is confined within a channel and utilize the acceleration ofthe fluid, while it is in contact with a turbine or rotor, characterizedby a change in the hydrostatic pressure of the fluid while in contactwith the turbine/rotor, to drive rotation of the turbine/rotor. Thepresent inventors have determined that the preferred liquid jet-drivenrotor mechanism provided according to the invention can, under certainconditions, provide improved efficiency of operation as well as improvedtorque vs. load characteristics, as compared with prior art mechanisms.

[0084] Also, as described in more detail below, for many embodiments ofthe invention, it is often desirable to provide a mechanism fordrivingly coupling a liquid jet-driven rotor to a rotatable shaft of asurgical instrument so that the rotational speed of the rotatable shaftis different from that of the rotational speed of the liquid jet-drivenrotor. Such rotational speed-changing drive mechanisms are well know tothose of ordinary skill in the art. In the context of the presentinvention, a preferred drive coupling mechanism utilizes a gearreduction drive. The gear reduction drives utilized according to theinvention can be configured in a variety of forms as apparent to thoseof ordinary skill in the art, including, but not limited to, screws andworm gears, helical gears, spur gears, etc. Some preferred embodimentsof the invention utilize a gear reduction drive coupling mechanismproviding a rotational speed of the rotatable shaft that is a definedfraction of the rotational speed of the liquid jet-driven rotatablerotor. By utilizing such a gear reduction mechanism, the maximum torqueobtainable at the distal end of the rotatable shaft for rotating atissue contacting surgical component, such as a grinding burr, can belarger, by a factor of the degree of gear reduction, than the torquethat would be obtainable utilizing a direct drive coupling mechanismwith the same diameter rotatable rotor. This can enable the use of asmaller diameter rotatable rotor for obtaining a particular value ofmaximum torque under maximum load conditions (i.e., when the rotatableshaft is completely stalled so that its rotational speed is essentiallyzero). As will be discussed in more detail below, a particularlyadvantageous configuration of a driving mechanism for providing rotarymotion to the rotatable shaft, according to the invention, utilizes aliquid jet-driven rotatable rotor that rotates about an axis of rotationthat is essentially perpendicular to the axis of rotation of therotatable shaft (defined by the longitudinal axis of the shaft) of thesurgical instrument. This configuration provides a compact and effectivemeans for coupling rotation of the rotatable rotor to the rotatableshaft through the gear reduction mechanism.

[0085] The inventive surgical instruments will now be described in moredetail in the context of several specific embodiments illustrated in theappended figures. It is to be understood that the embodiments describedare for illustrative purposes only and that the novel features of theinvention, as described in the appended claims can be practiced in otherways or utilized for instruments having other configurations, asapparent to those of ordinary skill in the art.

[0086]FIG. 1 shows one embodiment of a surgical instrument 100, providedaccording to the invention. Surgical instrument 100 illustrated isconfigured as a surgical handpiece having a proximal end 102 including abody 104 having grasping regions 106 configured for placement in thehand of an operator of the instrument. Body 104 as shown can be formed,in preferred embodiments, from a rigid plastic material, and ispreferably configured so that it can be separated into adjoiningsections so that components disposed within the body may be accessible.In the illustrated embodiment, body 104 comprises two halves 108, 110joined together by means of screws 112 which mate with threaded bores114. It should be understood that a variety of other means of joiningthe sections of the housing together can be utilized, as apparent tothose of ordinary skill in the art, for example, such means includingbut not limited to, ultrasound welding, snap fitting, solvent welding,etc.

[0087] Surgical instrument 100 has a distal end 116 including a pressurelumen 118 and an evacuation lumen 120. Distal end 116 of instrument 100further includes a rotatable grinding burr 122 disposed at the distalend of a rotatable shaft 124 (seen more clearly in FIG. 2A). “Distalend” when used herein in the context of a region of a surgicalinstrument refers to a portion of a surgical instrument that is adaptedto perform a surgical procedure on a patient and which is inserted intoa surgical field during operation of the instrument. The distal end 116of instrument 100 can, in some embodiments, comprise only the distalends 126, 128 of pressure lumen 118 and evacuation lumen 120respectively as well as the distal end 130 of rotatable shaft 124 (seeFIG. 2A) including grinding burr 122. In other embodiments, distal end116 of instrument 100 can also include components proximal to the distalends of the pressure lumen, evacuation lumen, and rotatable shaft thatare also inserted into a surgical operating field of a patient duringoperation of the instrument. In addition, in other embodiments, notshown, the instrument may provide only a rotatable shaft and may notinclude a pressure lumen and an evacuation lumen at the distal end ofthe instrument. In yet other embodiments, the instrument may not includea rotatable shaft and grinding burr as shown but may instead includeonly a pressure lumen at the distal end of the instrument or, in otherembodiments, a pressure lumen together with a target or evacuation lumenpositioned opposite the pressure lumen to receive a liquid cutting jet.

[0088] In the illustrated embodiment, surgical instrument 100 furtherincludes a sheath 132 which at least partially surrounds pressure lumen118, evacuation lumen 120, and rotatable shaft 124. As explained in moredetail below, sheath 132 aids in supplying support for the lumen toassist in maintaining and/or establishing a desired geometricconfiguration between pressure lumen 118 and evacuation lumen 120 toprevent relative motion of the lumen and misdirection of a liquidcutting jet. In addition, sheath 132 can be used for providing supportand evacuation to distal end 130 of rotatable shaft 124. As discussed inmore detail below in the context of FIGS. 2A-2C, removably coupled todistal end 116 and sheath 132 is burr tip support 136 including a snaptab 138 which fits into snap-lock slot 140 on sheath 132 to enableremovable coupling thereto. Burr tip support 136 also serves to providea bearing surface for distal end 130 of rotatable shaft 124, as well asto provide support to pressure lumen 118 and evacuation lumen 120.

[0089] Proximal end 142 of sheath 132 is sealingly coupled to the distalend of collar 144, whose function will be more thoroughly explained inthe context of FIG. 4 below. Collar 144 includes a seating flange 146which is held in place by slots 148 in body 104 when the instrument isassembled. Flange 146 also includes projecting ridge 150 which mountswithin a complementary groove within body 104, in order to preventcollar 144 from rotating during operation of the instrument.

[0090] Contained within body 104 of instrument 100 is driving mechanism152 configured for driving rotatable shaft 124. The specific details ofthe structure and operation of driving mechanism 152 are described inmore detail below in the context of FIGS. 8A-8E. Drive mechanism 152includes a liquid jet-driven rotor and gear reduction mechanism, shownand described in more detail below, enclosed in a three-part rotorhousing 154 held together by screw fasteners 156 and comprising an upperrotor housing cap 158, a rotor housing block 160, and a rotor housingbottom component 162. High pressure liquid is supplied to drivemechanism 152 via rotor drive pressure lumen 164. Rotor housing 154 isevacuated of liquid via rotor jet evacuation lumen 166, rotor housingblock evacuation conduit 168, and rotor housing bottom evacuationconduit 170. Also visible in FIG. 1 is rotor bearing 172. Bearings foruse in the current invention for rotatably mounting a rotor orcomponents of drive mechanism 152 coupled to rotatable shaft 124 cancomprise any suitable type of bearing known in the art, for example ballbearings, journal bearings, or hydrodynamic bearings. In the illustratedembodiment, the bearings comprise ball bearings.

[0091] Also contained within body 104 is rotatable shaft evacuationconduit 174 for providing evacuation to sheath 132 surrounding therotatable shaft and disposed in proximity to grinding burr 122. Body 104also includes an evacuation conduit connecting block 176, which servesto couple the evacuation conduits (168, 170, and 174) and evacuationlumen 120 and 166 to evacuation tubing 178 exiting the proximal end ofthe instrument. Connecting block 176 can include any one of a variety oflow pressure tubing connectors known to those of ordinary skill in theart, such as barbed connectors, Leur-lock connectors, press-fitconnections, etc.

[0092] In the illustrated embodiment, including both a pressure lumen118 for forming a liquid cutting jet at the distal end 116 of theinstrument and a pressure lumen 164 for forming a liquid jet thatprovides rotational driving force to a rotatable shaft, a liquid flowdirecting valve 180 may be included. The structure and function ofliquid flow directing valve 180 is described in greater detail below inthe context of FIG. 12. Liquid flow directing valve 180 has an inlet 182coupled to high pressure liquid supply conduit 184 by means of amanually tightenable high pressure tubing coupling 186. Valve 180 alsoincludes a first outlet 188 that is coupled via high pressure connector190 to pressure lumen 118 supplying high pressure liquid to nozzle 192disposed at distal end 116 of the instrument for forming a liquidcutting jet. Valve 180 also includes a second outlet 194 coupled viahigh pressure connector 196 to pressure lumen 164 supplying highpressure liquid to rotatable shaft drive mechanism 152. Liquid flowdirecting valve 180 can be manually adjusted by an operator, via slidingmotion of knobs 197, which are coupled to a shaft 198 (see FIG. 12), toenable liquid supplied via conduit 184 to be directed to either pressurelumen 118 or pressure lumen 164, depending upon the position of knobs197, or to be directed to both pressure lumens simultaneously.

[0093] High pressure connectors 186, 190, and 196 may comprise any typeof suitable high pressure connection known to those of ordinary skill inthe art that is capable of withstanding, for example, pressures inexcess of 1,000 psig, and preferably is capable of withstandingpressures up to at least about 50,000 psig. Such connectors may comprisewelded/brazed fittings, flanged fittings, swaged fittings, etc., asapparent to those of ordinary skill in the art. In a preferredembodiment, as illustrated, the high pressure fittings utilized includehighly compressed elastomeric O-rings and are configured as described incommonly owned U.S. Pat. No. 5,713,878, incorporated herein byreference.

[0094]FIG. 2A is an exploded perspective view of the portions ofsurgical instrument 100 disposed distal to body 104. As illustrated inFIG. 2A, rotatable shaft 124, pressure lumen 118 and evacuation lumen120 are shown removed from sheath 132 for clarity. Pressure lumen 118and evacuation lumen 120 are preferably constructed from a surgicalgrade stainless steel, however, in alternative embodiments, either orboth of the lumen may be constructed from other suitable materials, forexample certain polymeric materials, as apparent to those of ordinaryskill in the art. Regardless of the specific material from which thepressure lumen is constructed, pressure lumen 118 (as well as pressurelumen 164 supplying drive mechanism 152) must have sufficient burststrength to enable the lumen to conduct a high pressure liquid to thenozzle, for example nozzle 192, at the distal end of the pressure lumenin order to form a liquid jet. The burst strength of the pressure lumenutilized in the surgical instrument should be selected to meet andpreferably exceed the highest contemplated pressure required for use inthe specific surgical procedure to be performed. Typically, surgicalinstrument 100 will operate at liquid pressures of between about 500psig and about 50,000 psig, depending on the intended material to be cutand/or ablated and/or the required rotational speed and maximum torqueof the rotatable shaft. Those of ordinary skill in the art will readilybe able to select appropriate materials for forming the pressure lumenof the instrument and the evacuation lumen for particular surgicalrequirements based on the functional requirements of each describedherein.

[0095] Also illustrated in FIG. 2A is a preferred configuration forsupporting rotatable shaft 124 and lumens 118 and 120 within sheath 132.Rotatable shaft 124 includes a coupling region 200, having a reducedcross-sectional area and a non-circular cross sectional shape, disposedat its proximal end. Coupling region 200, as described in more detailbelow, enables rotatable shaft 124 to be coupled in driving engagementwith shaft drive mechanism 152. Supporting the distal end 130 ofrotatable shaft 124 is burr tip support 136. Shown in more detail inFIG. 2B and FIG. 2C, burr tip support 136, when assembled, provides acentral shaft bearing region 202 surrounding a region 204 of rotatableshaft 124 having a circular cross sectional shape and a reduced crosssectional dimension when compared to the central region 205 of rotatableshaft 124. Region 204 is surrounded by shaft distal bearing region 202of burr tip support 136 and rotates therewithin, when the instrument isin operation. Longitudinal movement of rotatable shaft 124 with respectto burr tip support 136 and sheath 132 is prevented by shaft bearingflange 206 and bearing lip 208 of rotatable shaft 124.

[0096]FIG. 2C shows a cross-sectional view of burr tip support 136 asviewed from the distal end of the instrument. Burr tip support 136includes an upper support member 210 and a lower support member 212,which are separable one from the other when disassembled from sheath132, and which, when coupled together, form shaft bearing channel 202.As shown in FIG. 2C, burr tip support 136 further includes an evacuationlumen slot 214 and a pressure lumen slot 216 for holding and supportingevacuation lumen 120 and pressure lumen 118 within sheath 132respectively, when the instrument is assembled for use. Burr tip support136 also includes evacuation channel slots 218 which, when the device isassembled, provide fluid communication, between the inside of sheath 132and the region distal to burr tip support 136 within the surgical field,for evacuating tissue and debris surrounding grinding burr 122 from thesurgical field and away from the patient. As discussed in more detailbelow, this evacuation may be provided by means of a source of externalsuction coupled in fluid communication with the proximal end of sheath132 or, in alternative embodiments, may be generated by the rotation ofrotatable shaft 124 itself.

[0097] Burr tip support 136 enables easy disassembly and exchange ofrotatable shaft 124 and grinding burr 122. In this manner, a variety ofgrinding burrs, or other components for performing a surgical functionon tissue of a patient can be interchanged during the course of aprocedure or between surgical procedures. Replacement or exchange of arotatable shaft/burr element can be performed as follows. While in anassembled configuration, for example as shown in FIG. 1, the userdepresses snap tab 138 on the spring flange region 220 of burr tipsupport 136 and slides the burr tip support and rotatable shaft frombore 222 of sheath 132. Pressure lumen 118 and evacuation lumen 120 arerigidly connected at their proximal ends within body 104 of instrument100 and remain within the sheath during removal of the rotatable shaftand burr tip support. While removing burr tip support 136 from sheath132, the distal ends of pressure lumen 118 and 120 slide throughpressure lumen slot 216, including a nozzle slot 224 therein, andevacuation lumen slot 214. Upon removal of burr tip support 136 androtatable shaft 124, upper support member 210 and lower support member212 can be separated, rotatable shaft 124 can be exchanged with anotherrotatable shaft having, for example, a different component at a distalend thereof, the upper support and lower support can be reassembled, andthe burr tip support/rotatable shaft unit can be re-inserted into bore222 of sheath 132 until snap tab 138 snaps into snap lock slot 140 ofthe sheath, thus completing the exchange process. Those of ordinaryskill in the art will readily envision a variety of alternative meansfor providing exchangeability of rotatable shaft 124 of instrument 100,all of which are deemed to be within the scope of the present invention.

[0098] Upon assembly, burr tip support 136, in addition to providing adistal bearing for rotatable shaft 124, also supplies support forpressure lumen 118 and evacuation lumen 120 to assist in maintainingand/or establishing a desired geometric configuration between thepressure lumen and the evacuation lumen when instrument 100 is inoperation. In preferred embodiments, pressure lumen 118 and evacuationlumen 120 are supported by burr tip support 136, when the instrument isassembled, so that the distal ends of the lumen are sufficiently stiffto prevent deflection of the lumen, by, for example, contact withsurfaces within the surgical operating space, which deflection couldpotentially lead to misdirection of the liquid cutting jet formed bynozzle 192 as high pressure liquid flows therethrough so that thecutting jet is no longer incident upon jet-receiving opening 193 inevacuation lumen 120, thus potentially causing unintended tissue damageto the patient.

[0099]FIG. 3 is a perspective view showing surgical instrument 100 asviewed from a proximal end thereof. FIG. 3 illustrates the assembledsurgical instrument except excluding body 104 to show the internalcomponents with greater clarity. The particular view illustrated showsmore clearly the back view of shaft drive mechanism 152 showing shaftdrive bearing 230 as well as the locations for attachment to rotor drivejet evacuation lumen 166, rotor housing block evacuation conduit 168,and rotor housing bottom evacuation conduit 170. Also shown more clearlyis high pressure conduit 184 and evacuation conduits 178. High pressureliquid supply conduit 184 must have a burst strength capable ofwithstanding the highest liquid pressures contemplated for usinginstrument 100 for a particular surgical application. In someembodiments, high pressure liquid supply conduit 184 comprises aburst-resistant stainless steel hypotube constructed to withstand atleast 50,000 psig. In some embodiments, the hypotube may be helicallycoiled to improve the flexibility and maneuverability of surgicalinstrument 100. In preferred embodiments, especially those includingintegrated electrocautery as discussed below, high pressure liquidsupply conduit 184 is comprised of an electrically insulating materialsuch as a Kevlar®-reinforced nylon tube. The liquid contained inevacuation conduits 178 (as well as evacuation conduits 168, 170, and174 within the body of the instrument) is under relatively low pressureand, accordingly, the evacuation conduits may be constructed, inpreferred embodiments, of a low cost flexible material, for example,polymeric tubing such as polyvinyl chloride (PVC), silicone,polyethylene, rubber, etc., tubing. Evacuation lumen 120 and at leastthe distal end (i.e. that contained within housing 154 and surroundingthe rotor, as shown in FIGS. 8C-8E below) of evacuation lumen 166 arepreferably constructed of a rigid material, such as stainless steel. Inpreferred embodiments, evacuation conduits 178 should have a minimuminternal cross-sectional area that equals or exceeds the maximuminternal cross-sectional area of the evacuation lumens and conduitswithin body 104 of instrument 100 to which the evacuation conduits arecoupled in fluid communication.

[0100]FIG. 4 is a perspective illustration showing surgical instrument100 as viewed from its distal end 116. In FIG. 4, surgical instrument100 is shown without sheath 132 or body 104 to more clearly illustratethe internal configuration of the collar 144 providing fluidcommunication between sheath 132 and shaft evacuation conduit 174, aswell as to more clearly illustration of the distal side 153 of rotatableshaft drive unit 152.

[0101] Collar 144 is shown partially cutaway in FIG. 4. Collar 144 canbe comprised of a metal, such as surgical stainless steel, or in morepreferred embodiments, can be comprised of a rigid plastic, such aspolycarbonate, nylon, acetal polymers, etc., as apparent to those ofordinary skill in the art. Collar 144 has a distal end 145 with acentrally disposed bore 240 therethrough surrounding pressure lumen 118,evacuation lumen 120 and rotatable shaft 124. Bore 240 is sized andconfigured so that proximal end 142 of sheath 132 can be press-fittherein to form a continuous, leak-tight path for fluid communicationbetween shaft evacuation conduit 174 and evacuation channel slots 218 ofburr tip support 136, when the instrument is assembled as shown in FIGS.1 and 2A-2C. In the illustrated embodiment, evacuation is supplied tothe distal end of the instrument surrounding grinding burr 122 bycoupling shaft evacuation conduit 174 in fluid communication with asource of external suction, such as a suction pump or aspirator. Asdescribed below, in alternative embodiments, rotatable shaft 124 can beconfigured such that rotation of the shaft is able to impart a drivingforce for removing material from the region surrounding the grindingburr without requiring conduit 174 to be attached to the source ofexternal suction.

[0102] Collar 144 further includes a centrally disposed cavity 242therein having a distal region 244, which is conically tapered, and aproximal region 246, which is essentially cylindrical in shape. Distalend 248 of rotor housing base 162 is shaped to mate with inner sealingsurfaces 250 of cavity 242 in collar 144, to create a vacuum-tight sealbetween surface 252 of the distal end of the bearing block and innersealing surface 250 of the collar.

[0103] Distal end 248 of rotor housing base 162 includes grooves 254,256 machined therein, which grooves form channels for passage ofpressure lumen 118 and evacuation lumen 120 respectively. In order toprevent leakage of evacuated fluid and a loss of suction through grooves254 and 256 during operation of the device, a bead of sealant 258 can beused to surround the lumen and create a vacuum-tight seal with innersealing surface 250 of collar 144, upon assembly of the device. Suchsealant can be comprised of a polymeric foam or RTV sealant, as would beapparent to those of ordinary skill in the art.

[0104] Proximal end 248 of rotor housing base 162 further includes asheath evacuation channel 260 machined therein for providing a fluidflow path for transport of fluid and debris between cavity 262,comprising a sheath evacuation region, and evacuation conduit 174.During operation of the device, when a suction is applied to evacuationconduit 174, liquid and debris will flow into sheath 132 via evacuationchannel slots 218 of burr tip support 136, then through bore 240 ofcollar 144 into sheath evacuation cavity 262, through sheath evacuationchannel 260, and finally through evacuation conduit 174 for removal fromthe instrument.

[0105] Also shown in FIG. 4 are rotor jet pressure lumen mounting blocks264, 266 which are utilized to mount rotor drive pressure lumen 164 torotor housing block 160 via, for example, screws 268. As described inmore detail below, the rotor jet pressure lumen mounting blocks enabledprecise alignment and direction of the liquid jet formed by the nozzleof pressure lumen 164 onto an impacting surface of a rotor utilized fordriving rotatable shaft 124, when the device is in operation.

[0106]FIG. 5A illustrates an alternative embodiment for configuring thedistal end of a surgical instrument providing both a liquid cutting jetand a rotational grinding burr and also more clearly illustrates apreferred configuration for providing a liquid cutting jet nozzle andevacuation lumen distal end. Instrument 272 includes a proximal end 274and a distal end 276. Unlike the previously illustrated embodiment,instrument 272 includes a sheath 278 surrounding only rotatable shaft280 including, at its distal end, a grinding burr 282. Surgicalinstrument 272 further includes a pressure lumen 284 and an evacuationlumen 286, both of which are disposed external to sheath 278.

[0107] For embodiments of the invention utilizing rotating shaftsincluding grinding burrs at their distal ends, a wide variety ofgrinding burrs can be utilized depending on the needs of the particularsurgical application, as would be apparent to those of ordinary skill inthe art. For example, fluted burrs and diamond burrs of various shapesand sizes can be used. For example, spherical, cylindrical, oval, flat,pear or egg shaped burrs may be utilized of various sizes for particularsurgical applications. Typical burr sizes for use, for example, in bonegrinding for arthroscopic procedures, can have an outer diameter rangingfrom about 2 mm to about 6 mm with the number of flutes, for flutedburrs, ranging from about 2 to about 20. In one particular example,involving the use of a grinding burr for bone grinding in arthroscopicprocedures, a 5 mm outer diameter spherical, fluted burr having eightflutes is utilized.

[0108] In the configuration shown in FIG. 5A, distal tips 288 and 290 ofpressure lumen 284 and evacuation lumen 286 respectively are disposeddistally to grinding burr 282. In another embodiment shown in FIG. 5B,distal tips 288 and 290 may, alternatively, be disposed proximal togrinding burr 282.

[0109] Also shown in FIG. 5A is a preferred arrangement for formingnozzle 1;92 in a pressure lumen for creating a liquid jet, as well as apreferred configuration for the distal end 290 of the evacuation lumenof the surgical instrument configured to receive a liquid cutting jet.Pressure lumen 284, which is substantially identical in configuration topressure lumen 118 discussed above, comprises a tubular conduit having anecked region 292 of the conduit defining nozzle 192, which neckedregion has an internal cross-sectional area that is less than aninternal cross-sectional area of the tubular conduit outside of andproximal to necked region 292. The distal end of pressure lumen 284 isfurther configured to enable jet opening 294 to direct a liquid cuttingjet 296 in a direction essentially transverse to the longitudinal axis298 of pressure lumen 284. Specifically, nozzle region 292 is bent withrespect to longitudinal axis 298 of pressure lumen 284 outside of jetnozzle region 292, so that jet opening 294 emits a liquid jet 296 whosecentral region is directed along an axis 300 that is essentiallyperpendicular to longitudinal axis 298. In alternative embodiments, theangle formed between jet axis 300 and longitudinal axis 298 can be anyangle between about 0° and about 90° (as shown).

[0110] Nozzles provided according to the invention, both for formingliquid cutting jets and for forming liquid jets to drive rotationalcomponents of the instruments (as described in more detail below)preferably have a relatively large nozzle length to internal diameterratio. The nozzles for use in inventive surgical instruments, both forforming liquid cutting jets and for driving rotational motion of arotatable shaft, preferably have a region having a minimum internaldiameter, which region has a length that exceeds its minimum internaldiameter by at least a factor of about 2, more preferably by a factor ofabout 4, and even more preferably by at least a factor of about 6. Inother embodiments, the region has a length that exceeds its minimuminternal diameter by at least a factor of about 10. As will be discussedin more detail below, the greater the ratio of the length to minimuminternal diameter of the nozzle region, the more narrowly focused andcollimated will be the liquid jet that is emitted from the jet openingof the nozzle. For reasons described in more detail below, highlycollimated liquid jets are preferred both for forming liquid cuttingjets at the distal end of the inventive surgical instruments and fordriving rotational motion of rotatable rotors and shafts provided by theinventive surgical instruments. However, in general, nozzles with ratiosof length to minimum internal diameter that are very high, for examplegreater than about 10, tend to create a very high pressure drop throughthe nozzle during use without significantly improving the degree ofcollimation of the jet and, therefore, are less preferred for use in theinventive surgical instruments than nozzles having a ratio of length tominimum internal diameter of an intermediate value, for example about 6.

[0111] The present invention provides surgical liquid jet instrumentswhich are specifically designed and constructed for use in a particularsurgical environment. Specifically, certain embodiments of the inventionprovide surgical liquid jet instrument designs that are tailored toprovide highly desirable liquid jet cutting characteristics in surgicaloperating environments where the liquid jet is submerged in a liquidenvironment when the instrument is in operation. More specifically, theinvention provides, in such embodiments, surgical liquid jet instrumentsincluding pressure lumen and evacuation lumen that are shaped, andpositioned relative to each other, to establish certain predeterminedgeometric relationships between the jet forming components andjet-receiving components that are specifically selected to provide thedesired performance characteristics of the instrument in a liquidsurgical environment.

[0112] Reference is made in FIG. 6A for describing the operation anddesign characteristics of preferred devices for use in forming a liquidcutting jet that is submerged in a surrounding liquid-containingsurgical environment. FIG. 6A shows a partially cutaway view of thedistal ends of pressure lumen 118 and evacuation lumen 120, which canform part of a surgical instrument, for example such as that shownpreviously in FIG. 1. Prior to operation, the distal ends of pressurelumen 118 and evacuation lumen 120 would be inserted into the operatingfield and at least partially submersed in a liquid 300 therein so thatat least nozzle 192 and jet-receiving opening 193 are completelysurrounded by liquid 300. When the instrument is in operation, liquidunder high pressure is delivered via pressure lumen 118 to nozzle 192,causing jet opening 294 to create a liquid cutting jet 296 as the highpressure liquid streams therethrough. As mentioned previously, it ispreferred that the jet 296 is substantially collimated as it exits jetopening 294. The more collimated a liquid jet, the less the liquid jetwill diverge or disperse as it traverses the gap between jet opening 294and jet-receiving opening 193. Thus, a highly collimated jet will have across-sectional shape and area at the jet-receiving opening 193 that issubstantially similar to the cross-sectional shape and area of theliquid jet at jet opening 294.

[0113] In general, the pressure of the high pressure liquid supplied tonozzle 192 for forming the liquid cutting jet 296 depends on theparticular design of nozzle 192 and the hardness/toughness of tissue ormaterial to be cut or ablated. Typically, the liquid at high pressure issupplied to jet opening 192 at a pressure of at least 500 psig, in otherembodiments at a pressure of at least about 5,000 psig, and still otherembodiments at a pressure of at least about 15,000 psig, and still otherembodiments at a pressure of at least 30,000 psig, and in yet stillother embodiments at a pressure of at least about 50,000 psig. Also asdiscussed previously, for embodiments where a collimated jet is desired,nozzle 192 preferably has a length to minimum internal diameter ratio ofat least about four, more preferably at least about six, and in otherembodiments at least about ten. Jet opening 294 typically has a circularcross-sectional area, but may, in other embodiments, have othercross-sectional shapes, such as rectangular, oval, slit-like, etc., forforming jets having different shapes for specific desired purposes. Inpreferred embodiments, jet opening 294 has an internal diameter ofbetween about 0.001 and about 0.02 inches, more preferably between about0.003 and about 0.01 inches, and most preferably about 0.005 inches.

[0114] Liquid cutting jet 296, which is collimated as it exits jetopening 294, tends to create a visible, opaque entrainment region 302surrounding liquid cutting jet 296. Entrainment region 302 is comprisedof rapidly moving liquid, which is entrained and driven by the kineticenergy of liquid cutting jet 296. Liquid cutting jet 296, as it rapidlymoves through liquid environment 300, also tends to create a zone of lowpressure, which is essentially coextensive with entrainment region 302.In typical embodiments involving high pressure liquids and rapidlymoving liquid jets, the pressure in entrainment region/low pressure zone302 will be lower than the vapor pressure of the surrounding liquid inliquid environment 300, thus causing cavitation of the liquid inentrainment region 302 and a resulting formation of an abundance ofextremely small gas bubbles 304 within the liquid in the entrainmentregion 302, making the region visually opaque.

[0115] As discussed previously, it is desired, in preferred embodiments,for safety and performance that the instrument be designed to reduce,and preferably eliminate, undesirable effects, such as blow-by of theliquid jet, plugging of the jet-receiving opening and the evacuationlumen, and inefficient tissue/debris entrainment and removal. Also, aspreviously mentioned, in preferred embodiments, it is desirable thatablated tissue and debris be evacuated from the surgical site throughthe evacuation lumen, without the need for a source of external suctionto be applied to the proximal end of the evacuation lumen. In order toprovide the above-mentioned characteristics, the inventive surgicalinstruments for use in a liquid environment can include an evacuationlumen having specifically selected predetermined shapes andconfigurations, which is positionable relative to the jet opening at aspecific predetermined distance. Specifically, in preferred embodiments,jet-receiving opening 193 is positioned, when the instrument is inoperation, opposite jet opening 294, at a predetermined distance #therefrom, and provided in a nozzle 192 having a length to minimumdiameter ratio so that essentially all of the fluid in liquid cuttingjet 296 enters jet-receiving opening 193. As discussed above, liquidcutting jet 296 will tend to create entrainment region 302 surroundingthe liquid cutting jet 296 when the instrument is in operation.Entrainment region 302 will typically be symmetrically deposed aroundliquid cutting jet 296 and will tend to diverge in a direction from jetopening 294 to jet-receiving opening 193. In typical embodiments wherejet opening 294 is circular in shape, entrainment region 302 will have atruncated cone shape, having a truncated apex at jet opening 294 and abase defined as a cross section of the cone at the plane ofjet-receiving opening 193. In preferred embodiments, the base ofentrainment region 302 occupies between about 50% and about 100% of thecross-sectional area of jet-receiving opening 193 when the instrument isin operation, more preferably the entrainment region occupies at leastabout 75%, more preferably still at least about 90%, and most preferablyat least about 95% of the cross-sectional area of jet-receiving opening193 when the instrument is in operation.

[0116] As shown in FIG. 6C, the cross-sectional area of thejet-receiving opening 193 required to ensure that the entrainment region302 occupies the desired relative fraction of the cross-sectional areaof the jet-receiving opening 193, as discussed above, is functionallyrelated to the chosen predetermined distance l between the jet opening294 and the jet-receiving opening 193 and the degree of divergencecharacterizing the entrainment zone (represented by angle φ in FIG. 6C).Specifically, the desired cross-sectional radius b of the base of theentrainment region 302 at the jet-receiving opening 193 is related topredetermined distance l and the degree of divergence of the entrainmentregion by b=l tan φ. Predetermined distance l is typically selectedbased on the desired use of the surgical instrument, dictating arequired fluid path cutting/ablating length. Based upon this desiredpredetermined distance l, the required size of the jet-receiving opening193 is typically determined experimentally by submersing the pressurelumen 118 and nozzle 192 in a liquid environment 300, forming a liquidcutting jet 296 by supplying a liquid to the nozzle 192 at a desiredpredetermined pressure, and visually observing the size of theentrainment region 302 or cavitation cone created around the liquidcutting jet 296, and estimating angle φ from the observations.

[0117] As mentioned above, the predetermined separation distance lbetween the jet opening 294 and the jet-receiving opening 193 dependsupon the requirements of the particular surgical procedure for which thesurgical instrument is used; however, for some typical embodiments, thepredetermined distance will have a maximum value of about 1 cm, forother typical embodiments, about 5 mm, and for yet other typicalembodiments, about 1 mm. The jet-receiving opening 193 typically willhave a diameter of between about 0.01 and about 0.2 inches, in otherembodiments between about 0.03 and about 0.1 inches, and in somepreferred embodiments a diameter of about 0.06 inches.

[0118] Referring again to FIG. 6A, a preferred configuration forevacuation lumen 120 will now be described. Preferred embodiments ofevacuation lumen 120 for use in surgical instruments intended to beoperated in a liquid environment include a maceration region 306 withinand/or downstream and in close proximity to the inlet to evacuationlumen 120 at jet-receiving opening 193. Maceration region 306 is definedas a region that contains a liquid undergoing intensely turbulent flowand impacting an internal surface of the evacuation lumen at an acuteangle, thus creating significant impacting forces capable of maceratingentrained material/tissue, when the instrument is in operation. Thecombination of the intensely turbulent flow of the liquid in macerationregion 306 and the impacting forces of liquid cutting jet 296 and theliquid in entrainment region 302 against the wall of evacuation lumen120 enable the liquid within the maceration region to macerate at leasta portion of any tissue or material entrained by the liquid inentrainment region 302 into a plurality of small particles. In preferredembodiments, the maceration region is able to macerate a substantialfraction (i.e., the majority of) the entrained tissue into a pluralityof small particles. In most preferred embodiments, the plurality ofparticles at least partially comprises a plurality of microscopicparticles too small to be seen unaided with the human eye. In all cases,the particles should be small enough to pass through evacuation lumen120 without plugging the evacuation lumen, when the instrument is inoperation.

[0119] In order to provide a maceration region, evacuation lumen 120preferably includes a jet-deflecting portion 308 that is locatedadjacent to and downstream of jet-receiving opening 193. Jet-deflectingregion 308 may be either a straight surface that is angled with respectto the direction of at least a central portion of liquid cutting jet296, or in preferred embodiments, jet-deflecting region 308 comprises asmoothly curved surface upon which at least a portion of liquid cuttingjet 296 impinges, where the curved surface is shaped to deflect at leasta portion, and preferably all of the liquid cutting jet 296 and liquidcomprising entrainment region 302 in a direction that is essentiallyparallel to the longitudinal axis 312 of evacuation lumen 120 in theregion proximal to the jet-deflecting region 308. In preferredembodiments, the radius of curvature of the curved surface definingjet-deflecting region 308 is essentially constant, having a value ofbetween about 0.5 and about 20 times the internal diameter of evacuationlumen 120. In one preferred embodiment, the radius of curvature of thecurved surface defining jet-deflecting region 308 is essentially equalto the internal diameter of evacuation lumen 120 at jet-deflectingregion 308, so that essentially no portion of jet-receiving opening 193projects radially beyond a perimeter defined by an outer surface 314 ofa portion of the evacuation lumen located proximal and adjacent tojet-deflecting region 308. It is also generally preferable for thesurgical instruments provided by the invention that the liquid cuttingjet be directed into the jet-receiving opening so that a direction of atleast a central portion of the liquid cutting jet forms an angle of nogreater than about 20 degrees, and more preferably no greater than about10 degrees, with respect to a line normal (i.e., perpendicular) to aplane defining (i.e., co-planar to) the jet-receiving opening. In themost preferred embodiments, the central portion of the liquid jet isessentially parallel to a line that is normal to the plane defining thejet-receiving opening.

[0120] In order to provide effective eductor pump action of evacuationlumen 120, in some embodiments, evacuation lumen 120 will have anessentially constant internal cross-sectional area from jet-receivingopening 193 to a position that is proximal to the distal end of thesurgical instrument where the proximal end of the evacuation lumen islocated. In other embodiments, eductor pump action can be enhanced byproviding an evacuation lumen having an essentially constantcross-sectional area and having a jet-receiving opening, which has across-sectional area that is less than the cross-sectional area of theevacuation lumen (i.e., the internal cross-sectional area of theevacuation lumen has a minimum value at the jet-receiving opening). Inyet other embodiments, eductor pump action can be enhanced by providingan evacuation lumen having an internal cross-sectional area whichincreases continuously from a minimum value at the jet-receiving openingto a maximum value at a predetermined position located proximal to thejet-receiving opening. In such embodiments, this maximum value of theinternal cross-sectional area should be essentially constant forpositions within the evacuation lumen that are proximal to theabove-mentioned predetermined position. In each of the above-mentionedembodiments, there are preferably essentially no reductions in theinternal cross-sectional area of the evacuation lumen at any positionproximal and/or downstream of the maceration region described above.

[0121]FIG. 6B shows an alternative design embodiment for theconstruction of the evacuation lumen for surgical instruments designedfor use in a liquid surgical environment. Evacuation lumen 320 includesa constriction 322 in the internal cross-sectional area of theevacuation lumen. The constriction 322 is located proximal tojet-receiving opening 324, and is preferably positioned immediatelyproximal and adjacent to maceration region 326. In operation, theconstriction 322 in the evacuation lumen 320 will act as a venturi asliquid within the evacuation lumen flows through the constriction, thusenhancing the eductor pump action of evacuation lumen 320. In theillustrated embodiment, constriction 322 comprises a pinch 328 in thesidewall of the tubing conduit comprising evacuation lumen 320. Inpreferred embodiments, the cross-sectional area of constriction 322should be between about three and about eight times the cross-sectionalarea of jet-opening 294 in nozzle 192.

[0122] Referring again to FIG. 6A, evacuation lumen 120 is shaped andpositioned relative to pressure lumen 118 so that at least a centralportion of liquid cutting jet 296 is directed into jet-receiving opening193 in a direction forming a non-zero angle with respect to (i.e.non-parallel with) the longitudinal axis 312 of evacuation lumen 120 ina region proximal to jet-deflecting region 308. In some embodiments,this angle can be between about 45 degrees and about 115 degrees, inother embodiments between about 80 degrees and about 100 degrees, and insome preferred embodiments, as illustrated, the angle can be about 90degrees.

[0123] As described above, in some embodiments of the inventioninvolving surgical instruments including rotatable shafts, liquid anddebris surrounding a grinding burr, or other tissue contacting componentat a distal end of the rotatable shaft, can be evacuated by coupling asheath of the instrument surrounding the rotatable shaft to a source ofexternal vacuum or suction. In other embodiments, also as mentionedabove, rotation of the rotatable shaft itself may be utilized togenerate an evacuating force for removing liquid and debris from an areasurrounding the distal end of the rotatable shaft. FIG. 7A shows apartial section of a distal region of rotatable shaft 400 that isconstructed and arranged to generate an evacuation force tending todrive liquid and debris from the distal end of a sheath surroundingshaft 400, when it is assembled within a surgical instrument accordingto the invention, to the proximal end of such sheath. “Constructed andarranged to generate an evacuation force” as used herein in the presentcontext refers to the ability of a rotatable shaft, rotating eitherwithin a surrounding sheath or without a surrounding sheath, to be ableto drive liquid from a region near the distal end of the rotatable shafttowards the proximal end of the rotatable shaft and out of a surgicalfield into which a distal end of the rotatable shaft is placed, withoutthe need for an external source of suction.

[0124] In operation, rotatable shaft 400 rotates in a direction shown byarrow 402. Rotatable shaft 400 includes a portion 404 of increased crosssectional dimension, preferably having a cross sectional dimension onlyslightly less than an internal cross sectional dimension of asurrounding sheath in which rotatable shaft 400 is disposed whenassembled into a surgical instrument. Region 404 includes a helicallygrooved channel 406 machined therein. Both region 404 and channel 406are positioned on shaft 400 so that they are surrounded by a sheath whenassembled into a surgical instrument. Rotation of shaft 400 in thedirection of arrow 402 during operation creates a driving force tendingto move fluid and debris from the distal end of shaft 400, in proximityto grinding burr 408, to a proximal end of the shaft and out of thesurgical field in which burr 408 is operating.

[0125]FIG. 7B shows a partial view of a distal region of an alternativeembodiment of a rotatable shaft 410 that is constructed and arranged togenerate an evacuation force upon rotation in the direction of arrow412. Shaft 410 includes grinding burr 414 at a distal end thereof, andfurther includes impellers 416, which are disposed within a surroundingsheath when shaft 410 is assembled into a surgical instrument, accordingto the invention. Upon rotation within the surrounding sheath, impellers416 generate an evacuation force tending to drive liquid and debristowards the proximal end of the shaft during operation of theinstrument.

[0126]FIG. 7C shows yet another embodiment of a rotatable shaftconstructed and arranged to generate an evacuation force upon rotation.Rotatable shaft 416, having grinding burr 418 at a distal end thereof,has an interior that is hollow forming a channel 420, which extendsdistally up to at least aperture 422 in scoop 424 (scoop 424 togetherwith aperture 422 will be hereinafter collectively referred to as a“scoop-shaped aperture” 425). Aperture 422 is in fluid communicationwith channel 420 formed along the hollow shaft of rotatable shaft 416.Upon rotation of shaft 416 in the direction of arrow 426 scoop-shapedaperture 425 scoops fluid and debris into aperture 422 and creates adriving force tending to move the fluid and debris in the direction ofarrow 428 towards the proximal end of shaft 416. In preferredembodiments, the scoop-shaped aperture 425 is disposed within asurrounding sheath when shaft 416 is assembled into a surgicalinstrument, according to the invention, and the scoop-shaped aperture425 is shaped and positioned to be able drive liquid and debris throughchannel 420 toward the proximal end of the surgical instrument uponrotation of shaft 416 during operation of the instrument. “Shaped andpositioned to drive liquid and debris” when used in the context of thescoop-shaped aperture 425 refers to a projecting scoop 424 having anaperture 422 therein that is in fluid communication with a centralchannel 420 of a shaft 416 that rotates in a given direction 426, wherethe aperture 422 within the scoop 424 faces in a direction with respectto the rotation of the shaft such that upon rotation of the shaft,liquid and debris tends to be forced through the aperture and into andalong the channel defined by the hollow shaft. As will be discussed ingreater detail in the context of FIGS. 11A-11B, for embodimentsincluding rotatable shafts that generate their own evacuation force, inaddition to evacuating a region of a surgical field surrounding thedistal end of the rotatable shaft, the evacuation force created by therotating shaft may also be used to create an evacuation force tending toevacuate other regions of the surgical instrument, for example regionsof the housing containing the drive mechanism for the rotatable shaft.

[0127]FIG. 8A shows an exploded perspective view of one preferredembodiment for rotatable shaft drive mechanism 152. Rotatable shaftdrive mechanism 152 includes a liquid jet-driven rotatable rotor 450,which in the embodiment illustrated in FIG. 8A comprises a saw-toothrotor. Upon assembly of the three subcomponents of rotor housing 154(i.e., rotor cap 158, rotor housing block 160 and rotor housing bottom162), rotatable rotor 450 is contained and rotates within a rotor slot452 included in rotor housing block 160 and rotor housing cap 158.Rotatable rotor assembly 454 includes, in addition to rotatable rotor450, rotor bearings 172 and 456 disposed at each end of a central shaft458, upon which the assembly rotates. Bearings 172 and 456 are heldwithin flanges 460 and 462 upon assembly of the rotor housing.

[0128] Rotor assembly 454, in the illustrated embodiment, also includesa worm gear 464 which mates with a complementary worm wheel 466 locatedon rotatable shaft drive assembly 468 (shown more clearly in anassembled state in FIG. 8B). Gear reduction mechanisms utilizing wormgears, such as illustrated in FIG. 8A, are preferred for someembodiments because they provide relatively high gear reduction ratiosfor their size. In other embodiments, where a lower degree of gearreduction and a lower difference in rotational speed between rotatablerotor 450 and drive shaft 470 of rotatable shaft drive assembly 468 isrequired or desired, other means of gear reduction, for example spurgears, helical gears, or any other suitable gear reduction mechanismsapparent to those of ordinary skill in the art can be utilized. Inaddition, for embodiments where high speeds are required or desired oronly low torques are necessary during operation, the gear reductionmechanism may be eliminated entirely and the rotatable rotor assembly454 may be utilized to drive rotatable shaft 124 directly. In such anembodiment, rotatable shaft drive mechanism 152 could dispense entirelywith rotatable shaft drive assembly 468, and instead couple therotatable shaft 124 directly to rotatable rotor assembly 454. Of course,in such embodiments, it is desirable to position rotatable rotorassembly 454 so that its longitudinal axis 472 is aligned parallel tolongitudinal axis of rotatable shaft 124 (i.e., it would be desirable toorient rotatable rotor assembly 452 in the orientation currently shownfor rotatable shaft drive assembly 468 in FIG. 8A).

[0129] Rotatable shaft drive assembly 468, as illustrated, is comprisedof drive shaft 470 to which is attached worm wheel 466. The assemblyalso includes two shaft drive bearings 230 and 474 which permit rotationof drive shaft 470 upon assembly of rotatable shaft drive mechanism 152.Bearings 230 and 474 are held by flanges (e.g., 476) provided in thehousing components, upon assembly of the mechanism. Bearings 172, 456,230, and 474, as illustrated, comprise ball bearings; however, inalternative embodiments the bearings may comprise journal bearings,hydrodynamic bearings, or any other suitable bearings as apparent tothose of ordinary skill in the art.

[0130] The components comprising rotatable shaft drive mechanism 152 arepreferably formed from a rigid, durable material, such as a variety ofmetals, for example surgical grade stainless steel. Because rotatablerotor assembly 454 and rotatable shaft drive assembly 468 rotate at highvelocity during operation of the instruments, it will be apparent tothose of ordinary skill in the art that the rotatable rotor 450, wormwheel 466, and other components comprising the assemblies should beproperly balanced so that they can rotate at high rotational speedswithout undue vibration of the instrument. Rotatable shaft driveassembly 468 further includes attached to its distal end rotatable shaftmounting component 480 having a distal surface 482 including a rotatableshaft mounting slot 484 that is sized and shaped to surround and coupleto coupling region 200 of rotatable shaft 124, when the instrument isfully assembled.

[0131] Rotatable shaft drive mechanism 152 includes pressure lumen 164which supplies high pressure liquid to nozzle 490 having jet opening 492therein for forming a liquid jet that is directed to impinge uponrotatable rotor 450, thus driving rotation of the rotor and therotatable shaft, when rotatable shaft drive mechanism 152 is assembledand operated. Upon assembly, as previously illustrated in FIG. 4,pressure lumen 164 is held in position to rotor housing block 160 bymeans of rotor jet pressure lumen mounting blocks 264, 266. Uponassembly and attachment of pressure lumen 164 to rotor housing block160, nozzle 490 passes into rotor housing block 160 through orifice 494so that jet opening 492 is oriented to properly direct a liquid jet atrotatable rotor 450 (shown more clearly in FIGS. 8C and 8D and discussedbelow). In addition, and not shown in the current figure, rotor jetevacuation lumen 166, rotor housing cap evacuation conduit 168, androtor housing bottom evacuation conduit 170 are connected to the variouscomponents of rotatable shaft drive mechanism 152, as shown anddiscussed previously, to enable essentially complete evacuation ofliquid from the internal spaces surrounding the rotatable components ofthe mechanism, upon assembly of the mechanism, to prevent submersion ofrotatable rotor or the rotatable components in liquid, when theinstrument is in operation.

[0132]FIG. 8B is a perspective view of rotatable rotor assembly 454 androtatable shaft drive assembly 468 as they are coupled upon assembly ofrotatable shaft drive mechanism 152. As shown in FIG. 8B, the varioushousing components have been eliminated to show assemblies 454 and 468with greater clarity. As is shown in the figure, for embodiments havinga drive mechanism including gear reduction (e.g., provided by worm gear464 and worm wheel 466 as illustrated) it is preferred to alignrotatable rotor assembly 452 such that its longitudinal axis 472 isessentially perpendicular to longitudinal axis 496 of rotatable shaftdrive assembly 468.

[0133] As will be apparent to those of ordinary skill in the art, theparticular rotational speeds of rotor 450, rotor drive assembly 454, anddrive shaft 470 of rotatable rotor drive assembly 468 must be selectedbased upon the needs of the particular surgical application and on thecharacteristics of the particular rotatable component being utilized fortissue contact and being rotated by the rotatable shaft. For typicalapplications utilizing the inventive surgical instruments, therotational speed of rotatable rotor 450 will be at least about 16,000RPM, in other embodiments at least about 65,000 RPM, in yet otherembodiments at least about 130,000 RPM, in yet other embodiments atleast about 250,000 RPM, and in still other embodiments at least about500,000 RPM. The diameter of rotatable rotor 450 is typically at leastabout 0.5 inch, in other embodiments at least about 1 inch, in otherembodiments at least about 2 inches, in other embodiments at least about5 inches, and in yet other embodiments at least about 10 inches. Thegear reduction mechanism is selected and configured in preferredembodiments, so that the rotational speed of rotatable rotor 450 willexceed the rotational speed of drive shaft 470 of rotatable rotor driveassembly 468. In typical embodiments, the rotational speed of rotatablerotor 450 will exceed that of drive shaft 470 by at least about a factorof 2, in other embodiments by at least about a factor of 5, in otherembodiments by at least about a factor of 10, in other embodiments by atleast about a factor of 20, and in yet other embodiments by at leastabout a factor of 30. In one particularly preferred embodiment involvinga surgical instrument including a rotatable shaft having a 5 mm diameterfluted burr at a distal end thereof, which is utilized for bone grindingin a surgical operating field, rotatable rotor 450 comprises a 1 inchdiameter saw-tooth rotor having between about 10 and 200 teeth, and inone preferred embodiment about 80 teeth, which is driven at a rotationalspeed during operation of about 130,000 RPM and is coupled to driveshaft 470 via a worm-gear reduction mechanism such that the rotationalspeed of drive shaft 470 is about {fraction (1/10)}th that of rotatablerotor 450 during operation.

[0134] For embodiments utilizing a rotatable rotor which is a saw-toothrotor, depending on the diameter of the saw-tooth rotor and the size ofthe teeth when compared to the diameter of the rotor, the number ofteeth provided on the rotor can range from about 10 to about 200. Asdiscussed immediately above, one particularly preferred saw-tooth rotorembodiment comprises a 1 inch diameter rotor having a thickness of about0.040 inch and having about 80 teeth therein, each tooth providing a jetimpacting surface about 0.040 inch wide by 0.040 inch in height.

[0135]FIGS. 8C-8E are detailed views of rotatable rotor 450 androtatable rotor assembly 454 showing the configuration of the rotatablerotor with relation to liquid jet forming nozzle 490 and rotor jetevacuation lumen 166, when rotatable shaft drive mechanism 152 isassembled. For clarity, components other than the rotatable rotorassembly, pressure lumen and evacuation lumen are not shown in thefigures. Referring to FIG. 8C, rotatable rotor 450 comprises a saw-toothrotor including a plurality of teeth 498 each including an essentiallyplanar impacting surface 500 upon which liquid jet 502 impacts, when theinstrument is in operation. Nozzle 490 of pressure lumen 164 ispreferably configured to create an essentially collimated liquid jet asa high pressure liquid streams therethrough. The particularconfiguration of nozzle 490 can be essentially equivalent to thatdiscussed previously with respect to preferred nozzles for formingliquid cutting jets at the distal end of the surgical instrument.Specifically, nozzle 490, in preferred embodiments, has a length tominimum internal diameter ratio of between about 2 and about 10 with apreferred length to minimum internal diameter ratio of about 6. Jetopening 492 is positioned at a selected predetermined distance from theimpacting surface 500 upon which liquid jet 502 impacts, when theinstrument is in operation. This predetermined distance, in preferredembodiments, is the minimum distance possible, without having teeth 498of the rotor impacting nozzle 490 upon rotation of the rotor. Forexample, when utilizing a 1 inch diameter saw-tooth rotor having teeth498 with a height of about 0.040 inch, the distance between jet opening492 and the impacting surface of the saw tooth upon which the liquid jetimpacts, is preferably less than about 1 cm, and more preferably lessthan about 1 mm.

[0136] In preferred embodiments, predetermined distance, nozzle lengthto minimum internal diameter ratio, and the size of each impactingsurface 500 are chosen so that essentially the entirety of liquid jet502 impacts an impacting surface 500 of the rotor during operation. Inother words, the above parameters are preferably selected so that at thepoint of impact 506 of liquid jet 502 with an impacting surface 500, thecross-section of liquid jet 502, within the plane of impacting surface500, is essentially entirely incident on impacting surface 500 so thatessentially no part of the liquid jet “misses” or “blows by” theimpacting surface. In such a situation, the momentum of the entireliquid jet can potentially be imparted to rotatable rotor 450 to createrotational motion of the rotor.

[0137] The distal end of rotor jet evacuation lumen 166 is shownpartially cutaway in FIG. 8C to more clearly show nozzle 490, liquid jet502, and rotatable rotor 450, as positioned within the distal end of thelumen. As shown more clearly in FIGS. 8D and 8E, the distal end ofevacuation lumen 166, which is disposed within rotor housing block 160upon assembly of rotatable shaft drive mechanism 152, includes a slit504 in which a portion of rotatable rotor 450 is located duringoperation. Furthermore, the distal end of pressure lumen 164 includingnozzle 490 is also positioned within and essentially completelysurrounded by the distal end of evacuation lumen 166 when the drivemechanism is assembled. This configuration serves to maximize thecontainment of any spray that is created upon the impacting of liquidjet 502 with an impacting surface 500 of rotatable rotor 450. This isespecially important for periods of operation of the instrument wherethe rotatable shaft of the instrument is subjected to significant torquetending to inhibit its rotation. During such periods of operation,rotatable rotor 450 will tend to rotate at a speed that is less than thevelocity of liquid jet 502. Under such conditions, liquid jet 502 canhave a tendency to form spray or mist upon impacting an impactingsurface 500. By contrast, under conditions of free rotation, rotatablerotor 500 rotates at a speed essentially equal to the speed of liquidjet 502, so that the trajectory of liquid jet 502 remains essentiallyconstant even after impacting an impacting surface 500, and minimalspray is created. In an alternative embodiment, the evacuation lumen canbe configured and positioned so that it does not surround and encloseany portion of the distal end of pressure lumen but, instead, ispositioned distally of the nozzle in the pressure lumen, preferably witha jet-receiving opening positioned within about 0.01 inch of the jetopening in the nozzle.

[0138] The design of evacuation lumen 166 as illustrated enableseffective evacuation of essentially all of the liquid comprising liquidjet 502 from the housing enclosing the rotatable rotor assembly duringoperation of the device under a wide range of loads and resistancesapplied to the rotatable shaft of the instrument. In certainembodiments, the proximal end of evacuation lumen 166 can be placed influid communication with a source of external suction in order to effectevacuation of liquid comprising liquid jet 502. In some preferredembodiments, liquid jet 502, via eductor pump action, describedpreviously, is able to create its own evacuation force tending toevacuate the liquid comprising liquid jet 502, together with any sprayformed upon impacting with a surface of the rotor, from the distal endof evacuation lumen 166 without the need for an external source ofsuction.

[0139] In typical embodiments, jet opening 492 in nozzle 490 has adiameter of between about 0.001 and about 0.02 inch, more preferablybetween about 0.003 and 0.01 inch, and in one preferred embodiment has adiameter of about 0.005 inches. In typical embodiments, liquid issupplied to nozzle 490 to form a liquid jet at a pressure of at leastabout 1,000 psig, in other embodiments at least about 5,000 psig, inanother embodiments at least about 15,000 psig, and yet in otherembodiments, at least about 30,000 psig. In one preferred embodiment,liquid is supplied to nozzle 490 to form a liquid jet at a pressure ofabout 8,000 psig. Evacuation lumen 166, in typical embodiments, has ajet receiving opening 508 having a diameter of between about 0.01 andabout 0.3 inches, more preferably between about 0.05 and about 0.2inches and in one preferred embodiment about 0.12 inches. As will bediscussed below in more detail in the context of FIGS. 11A-11B, forembodiments wherein liquid jet 502 is directed into an evacuation lumen166 creating an evacuation force by eductor pump action without the needfor an external source of suction, this evacuation force can be utilizednot only to evacuate liquid comprising liquid jet 502, but also toevacuate or assist in evacuating other components of the surgical liquidjet instrument.

[0140] Rotatable rotor 450 is shown schematically and in greater detailin FIGS. 9A and 9B. FIG. 9A shows rotatable rotor 450 as viewed from thesame orientation as shown in FIG. 8C above. FIG. 9A illustrates apreferred embodiment for orientating and directing liquid jet 502 at animpacting surface 500 of saw teeth 498 on rotatable rotor 450. FIG. 9Bshows rotatable rotor 450 as viewed from above, more clearly showing theorientation of the fluid jet within the plane of the rotor. Thedirection of the liquid jet is shown by arrows 510 and 512 in thefigures. As shown in the figures, it is preferred to direct the liquidjet towards surface 500 of rotatable rotor 450 so that it impacts thesurface at a non zero angle (i.e., the liquid jet is not directedtangentially to the surface). Even more preferably, as shown in FIG. 9B,the liquid jet is directed towards impacting surface 500 of rotatablerotor 450 such that the direction of the liquid jet 510, 512 isessentially perpendicular to the surface, at least as measured in thex-z plane as illustrated in FIG. 9B. As shown in FIG. 9A, in someembodiments, for example those having a liquid jet directed alongdirection 510, the liquid jet can be directed at surface 500 so that itis also essentially perpendicular to the surface as measured in the y-zplane, illustrated in FIG. 9A. In other embodiments, the liquid jet canbe directed along liquid jet direction 510, such that the liquid jet isdirected toward surface 500 at a relatively small angle as measuredwithin the y-z plane so that the liquid jet is angled somewhat toimpinge closer to the base 514 of saw tooth 498. The term “essentiallyperpendicular,” when used in the context of describing the direction ofa liquid jet with respect to an impacting surface of a rotatable rotor,refers to the liquid jet being directed towards the impacting surface ofthe rotatable rotor such that it is essentially perpendicular to thesurface in at least the x-z plane as illustrated in FIG. 9B.

[0141] Preferred saw tooth rotors have liquid jet impacting surfacesthat are essentially planar. Furthermore, as described above in thepreceding paragraph, the surfaces are preferably oriented with respectto the rotor such that each impacting surface is oriented essentiallyperpendicularly (or is essentially perpendicular to) a liquid jetimpacting thereon at at least one rotational position of the rotatablerotor. Furthermore, in preferred embodiments, each liquid jet impactingsurface 500 of rotatable rotor 450 is also oriented at an angle ofbetween about 75 degrees and about 105 degrees with respect to a line516 tangent to the circle circumscribed by the outermost perimeter ofthe rotor as it rotates about its axis of rotation 518. In someespecially preferred embodiments, each liquid jet impacting surface 500of rotatable rotor 450 is oriented essentially perpendicularly to line516

[0142] In alternative embodiments, a rotor having liquid jet impactingsurfaces that are curved may be utilized in place of a saw tooth rotorhaving planar impacting surfaces, as previously described. FIG. 10Ashows a perspective view of a curved-vane rotor 520 having curved liquidjet impacting surfaces 522. Curved impacting surfaces 522 are defined bya series of curved vanes 524 positioned along the periphery of rotor520. As illustrated, preferred curved-vane rotors have impactingsurfaces 522 that are oriented to provide an impacting surface that isconcave with respect to the direction of an incoming liquid jet, shownby arrow 526. In the illustrated embodiment, curved impacting surfaces522 comprise semi-cylindrical surfaces. For embodiments utilizing rotorshaving smoothly curved liquid jet impacting surfaces 522, it ispreferred for the liquid jet to be oriented in a direction 526 such thatit is directed toward surface 522 essentially tangentially to thesurface.

[0143]FIG. 10B illustrates a particularly preferred configuration fororienting and positioning curved vanes 524 around the periphery of rotor520. As illustrated in FIG. 10B, in a preferred embodiment, angle αformed between the line 523 tangent to impacting surface 522 of thecurved vane and the line 525 defining the edge of rotor 520 should bebetween about 5 degrees and about 30 degrees, and in a preferredembodiment is about 17 degrees. In addition, channel width h betweencurved vanes 524, through which the liquid comprising an impactingliquid jet flows when the rotor is in operation, is preferably betweenabout the diameter of the impacting liquid jet at the point of impactand a value of about twice the diameter of the liquid jet. In addition,the width of curved vanes 524 (C) is preferably chosen with respect tothe inter-vanes spacing (S) such that the ratio (C/S) is between about1.0 and about 1.5. In yet other embodiments, a smoothly curved jetimpacting surface may be provided by utilizing a Terry rotor for drivingthe rotatable shaft of the surgical instrument. Terry rotors are knownin the mechanical arts and are described in greater detail in, forexample, Balje, O. E. Turbomachines: A Guide to Design, Selection, andTheory, John Wiley & Sons, New York, N.Y., 1981, pp. 252-256.

[0144]FIGS. 11A and 11B show two potential configurations for supplyingevacuation to the various evacuation lumen and conduits of surgicalinstrument 100. In another embodiment, not illustrated, an externalsource of suction is coupled in fluid communication to each of theevacuation lumen and evacuation conduits of surgical instrument 100 inorder to provide a suction force to each that is generated by theexternal source of suction. In alternative embodiments, suction createdby the eductor pump action of cutting jet evacuation lumen 120, rotorjet evacuation lumen 164, and/or the suction force created by any of theself-evacuating rotatable shaft designs shown previously in FIGS. 7A-7Ccan instead be utilized to supply a source of suction for evacuatingvarious other evacuation conduits of instrument 100.

[0145]FIG. 11A illustrates one embodiment for evacuating the variousevacuation lumen and conduits of instrument 100. For the illustratedembodiment, the rotatable shaft of the surgical instrument would not beconfigured to provide self-evacuation. Accordingly, an external sourceof suction 530 is coupled in fluid communication to evacuation conduit532, which in turn, is in fluid communication with the sheath 132surrounding the rotatable shaft. By contrast, the remaining evacuationlines of the instrument are each connected to a manifold 534 configuredas shown. Fluid momentum supplied by the eductor pump action of therotor jet evacuation lumen 166 in combination with liquid cutting jetevacuation lumen 120 is utilized to create a suction force withinmanifold 534 sufficient to evacuate the evacuation conduit 168 connectedto rotor housing base 162 and the evacuation conduit 170 connected torotor housing cap 158. It should be understood that manifold 534 may beformed by connecting the exhaust lumen/conduits in the manner shown inFIG. 11A outside of the body of the surgical instrument (as would be thecase if using surgical instrument 100 as illustrated in FIG. 1 above);however, in other embodiments, manifold 534 can be configured to andcontained within the body of the surgical instrument.

[0146]FIG. 11B shows an alternative embodiment for a surgical fluid jetinstrument that includes a rotatable shaft configured to create anevacuation force upon rotation of the shaft, as previously described inFIGS. 7A-7C. With such a configuration, the external source of suctioncan be eliminated entirely, and the entire surgical instrument can beconfigured to be self-evacuating without the need for an external sourceof suction. In the illustrated embodiment, the various evacuation lumenand conduits are connected to a manifold 542. In the illustratedembodiment, the liquid momentum supplied by the eductor pump action ofrotor jet evacuation lumen 166 and liquid cutting jet evacuation lumen120 are utilized in combination with the liquid motive force supplied bythe rotatable shaft through sheath 132 to create a sufficient suction inmanifold 542 to evacuate evacuation conduit 168 connected to rotorhousing block 160 and evacuation conduit 170 connected to the rotorhousing base 162 of the surgical instrument.

[0147] A cross-sectional view showing the internal details of liquidflow directing valve 180 is illustrated in FIG. 12. Liquid flowdirecting valve 180 includes a valve body 550 formed of a rigid sturdymaterial, for example surgical grade stainless steel, having a centrallydisposed bore therein forming a cylinder 552 internal to valve body 550.Valve 180 is configured as a slidable three-way valve. Valve body 550further includes an inlet 182 comprising a bore having threaded wallsconfigured to mate with a high pressure tubing coupling 186 (shown inFIG. 1). Similarly, valve body 550 further includes a first 188 and asecond 194 outlet configured with internally threaded surfaces forcoupling to high pressure connectors 190 and 196 respectively.

[0148] Disposed within centrally disposed cylinder 552 is a shaft 554,preferably comprised of a rigid, durable metal such as surgical gradestainless steel, connected by threads 555 at each end to user actuatedknobs 197. Also disposed on shaft 554 are two elements 556 comprisingpressure tight sealing components for preventing leakage of highpressure liquid from and within valve 180. Elements 556 comprising thepressure tight sealing components are described in greater detail belowin the context of FIGS. 13A and 13B. Elements 556, while shown for usewithin the context of liquid flow directing valve 180, can also be usedfor a wide variety of other applications where a high pressure, slidablesealing component is needed to form a high pressure seal between a shaftor piston and the walls of a cylinder. Pressure tight sealing components556 are separated along shaft 554 by a cylindrical spacer sleeve 558surrounding shaft 554 and disposed between the pressure tight sealingcomponents. Pressure tight sealing components 556 are forced againstspacer 558 to prevent relative motion between shaft 554 and the pressuretight sealing components by tightening knobs 197 onto the threaded endsof shaft 554 to provide a biasing force pushing the pressure tightsealing components 556 against spacer 558.

[0149] Spacer 558 has an external diameter less than that of theinternal diameter of inner surface 560 of cylinder 552. Thus, a spaceprovided between the outer surface 562 of spacer 558 and the innersurface 560 of cylinder 552 defines a flow channel 564 through whichhigh pressure liquid flows from inlet 182 to either or both of outlets188 and 194, when the instrument is in operation. In some preferredembodiments, valve 180 can be adjusted by the user, by manipulating theposition of shaft 554 with knobs 197, to provide three user-selectablepositions. In especially preferred embodiments, the threeuser-selectable positions can be defined by discreet stops along thedirection of movement of shaft 554 within cylinder 552. For example, inone particular embodiment, the shaft and cylinder sliding mechanism canbe configured, upon a force applied to one or both of knobs 197 to movebetween three discreet positions along the length of travel of the shaftwithin the cylinder, each position defining a particular flow path andrequiring a force applied to knobs 197 to dislodge the shaft from thediscreet position. A variety of mechanisms for providing such discreetsliding action between predefined positions are well known to those ofordinary skill in the art. In other embodiments, where liquid flowexiting both outlets simultaneously is not desired, shaft 554 of valve180 may be configured, for example with a bistable mechanism, to permitvalve 180 to be adjusted by the user to one of two discreet positions,one for directing flow to outlet 188 and the other for directing flow tooutlet 194.

[0150] As illustrated in FIG. 12, shaft 554 has been moved to the farright of its permissible range of motion. This position defines a firstuser-selectable position directing a high pressure liquid from inlet 182through flow channel 564 and out of the valve through outlet 188, whichis fluid communication with pressure lumen 118 supplying high pressureliquid to liquid cutting jet nozzle 192 shown in FIG. 1. Such positionwould be selected by the user of the surgical jet instrument in order tocreate a liquid cutting jet with the surgical instrument withoutcreating rotation of the liquid jet-driven rotatable shaft of thesurgical instrument. A second user-selectable position would be theposition obtained by sliding shaft 554 to its leftmost range of travel.In this configuration, high pressure liquid would flow from inlet 182through flow channel 564 and out of the valve through outlet 194, whichis in fluid communication with rotor drive pressure lumen 164. Thisconfiguration can be utilized for driving a liquid jet-driven rotatableshaft of the instrument without simultaneously creating a liquid cuttingjet with the instrument. Yet a third user-selectable position, in someembodiments, can be achieved by positioning shaft 554 at a positionroughly equidistant between its rightmost and leftmost ranges of travel.In this third user-selectable position, high pressure liquid will flowfrom inlet 182 through flow channel 564 and out of the valve throughboth outlets 188 and 194. In this configuration, the user may create aliquid cutting jet with the instrument while simultaneously powering aliquid jet-driven rotational shaft of the instrument.

[0151] Elements 556 are shown in greater detail in FIG. 13. Element 556is configured as a pressure-tight sealing component. A “pressure-tightsealing component” as used herein refers to a component that is able toform a pressure-tight seal between two regions of a cylinder, eachcontaining a fluid therein, wherein the fluids contained in the tworegions are at different hydrostatic fluid pressures. A “fluid” when inthe present context can comprise a liquid, gas, supercritical fluid,slurry, suspension, or any mixture of the above, and refers to thethermodynamic state of the material present in the regions of thecylinder at the temperature and pressure at which the component is usedin operation. In the context of use of the pressure-tight sealingcomponent within liquid flow control valve 180, the fluid contained inat least one of the above-mentioned regions of the cylinder willcomprise a liquid; however, as apparent to those of ordinary skill inthe art, element 556 can also be used for a wide variety of otherpressure sealing applications not necessarily involving pressurizedliquids.

[0152] Element 556 is shown in cross section of FIG. 13 together with aportion of spacer 558. Shaft 554 has been removed in the figure to showthe illustrated components with greater clarity. Element 556 may becomprised of a wide variety of materials capable of withstanding thepressures contemplated, such as, for example, a variety of metals,ceramics, plastics, etc. Element 556 is, in preferred embodiments,comprised of a non-elastomeric, semi-rigid plastic that is dimensionallystable within the range of operating pressures contemplated. Preferredplastics include crystalline polymers or semi-crystalline polymers, oramorphous polymers having a glass transition temperature higher than theoperating temperature of the apparatus utilizing element 556 as asealing component. Element 556 can be constructed from a wide variety ofengineering plastics, for example, polytetrafluorethylene (PTFE),polypropylene, polyethylene, polyvinylchloride, polyamides, polysulfone,polystyrene, mixtures thereof, etc., as apparent to those of ordinaryskill in the art. In one particular preferred embodiment, element 556 isformed from an acetal polymer, for example, polyoxymethylene (Delrin™).

[0153] Element 556 includes an integral, flared sealing flange portion559 that is constructed and arranged to make sealing contact with theinternal surface 560 of cylinder 552 within valve 180, while preventingcontact between internal surface 560 and both shaft 554 and betweeninternal surface 560 and any other portion of element 556 outside offlange region 559. “Constructed and arranged to make sealing contact” asused herein in reference to flared sealing flange portion 559 refers toat least an outer surface 561 of the flange portion being sized andshaped to form an essentially continuous contact with inner surface 560of cylinder 552 (i.e., having an outer perimeter with a shapeessentially conforming to the shape of cylinder 552). It should beemphasized, that while, in the illustrated embodiment, the shape ofcylinder 552 and the outer perimeter of outer surface 561 is essentiallycircular in cross-section (i.e. cylinder 552 as illustrated comprises acircular cylinder), in other embodiments, the shape of the cylinder andthe outer perimeter of outer surface may be other than circular incross-section, for example, the cylinder may comprise a cylindricalchannel with a rectangular, elliptical, triangular, polygonal, or othercross-sectional shape, with the integral, flared sealing flange portionof the sealing element being similarly shaped so that that isconstructed and arranged to make sealing contact with the internalsurface of the cylinder. Flared sealing flange portion 559 of element556, when in sealing contact with inner surface 560 of cylinder 552,provides a leak-tight seal at the point of contact between the flaredsealing flange portion of the element and the internal surface of thecylinder that is able to withstand a differential in liquid pressure ofat least about 1,000 psi without leakage of liquid through the seal. A“differential in liquid pressure” as used herein in the present contextrefers to a difference in hydrostatic pressure between a liquidcontained within flow channel 564 of cylinder 552 and a pressure outsideof the region of flow channel 564 (e.g., atmospheric pressure) withincylinder 552. In more preferred embodiments, the seal formed betweenflange region 559 and surface 560 of cylinder 552 is capable ofwithstanding a differential in liquid pressure of at least 8,000 psi,more preferably at least 25,000 psi, and most preferably at least 50,000psi without leakage of liquid through the seal.

[0154] In the illustrated embodiment, element 556 is shaped to include amain body portion 563 having a cylindrical shape with an outer diameterD_(I). As illustrated, flange portion 559 of element 556 is formedintegral to surface 565 abutting spacer 558. Surface 565 also includes aridge 566 for seating against angled internal surface 568 of spacer 558.In other embodiments, flared sealing flange portion 559 may be locatedalong main body portion 563 at a position intermediate spacer abuttingsurface 565 and knob abutting surface 570. It should also be understoodthat in other applications element 556 may be configured as a cap havingsurface 565 extending completely across the centrally disposed bore 572within the interior of the element. Such a configuration couldpotentially be useful for use as a pressure sealing cap on the end of ashaft.

[0155] As configured for use in liquid directing valve 180, element 556has a main body portion 563 configured with a tube-like annular shape,wherein centrally disposed bore 572 is disposed entirely through thecentral region of the element, permitting the element to be mounted toshaft 554, which shaft passes through centrally disposed bore 572, whenthe element is mounted to the shaft.

[0156] Flared sealing flange portion 559 of element 556 has a predefinedlength 574 and is angled to extend away from outer surface 576 of mainbody portion 563 and toward inner surface 560 of cylinder 552 of valve180 when the valve is assembled. The flared sealing flange portion 559extends away from surface 576 of main body portion 563, as shown, toform a cantilevered circumferential flange around the periphery ofelement 556. A “cantilevered circumferential flange” refers to a flangethat circumscribes the entire outer perimeter of the main body portionof the element and is attached to the main body portion along one of itssides, while having at least two additional sides or faces (e.g.,surfaces 561, 577, and 578) not attached to or integral with the mainbody portion of the element (i.e., having a triangular cross-sectionalshape or a trapezoidal or rectangular cross-sectional shape).

[0157] Predefined length 574 and minimum thickness 580 of sealing flangeportion 559 tend to vary approximately linearly with the size ofcylinder 552 in which sealing element 556 is disposed during operation.In one exemplary embodiment utilizing a Delrin plastic element having amain body portion with an external diameter D_(I) of about 0.182 inchthat is used as a pressure-tight sealing component within a cylinderhaving an internal diameter of about 0.1875 inch, length 574 is about0.025 inch and thickness 580 is about 0.003 inch.

[0158] Sealing element 556 has a second outer diameter D_(O) defined byan outermost periphery 582 of flange portion 559 that exceeds the outerdiameter D_(I) of main body portion 562. When element 556 isdisassembled from cylinder 552 of valve 180, outer diameter D_(O) of theoutermost periphery 582 of flange portion 559 exceeds outer diameterD_(I) of main body portion 563 by at least about 1%, in otherembodiments by at least about 3%, in other embodiments by at least about5%, and in yet other embodiments by at least about 10%. In one preferredembodiment, outer diameter D_(O) exceeds diameter D_(I) by about 5%.Cylinder 552 of valve 180, containing element 556 upon assembly of thevalve, has an internal diameter that exceeds outer diameter D_(I) ofmain body portion 563 but that is somewhat less than outer diameterD_(O) of outermost periphery 582 of flange portion 559 of element 556.It should be emphasized that outer diameter D_(O) of outermost periphery582 of flange portion 559 as described herein refers to the diameter asmeasured with element 556 disassembled from valve 180 and not containedwithin cylinder 552. When element 556 is inserted into cylinder 552,flange portion 559, which is pivotally flexible with respect to mainbody portion 563, will tend to have a maximum outer diameter ofoutermost periphery 582 of flange portion 559 that is essentially equalto the inner diameter of cylinder 552. Referring now to the maximumouter diameter D_(O) of outermost periphery 582 of flange portion 559,as measured with element 556 not assembled into cylinder 552, cylinder552 typically has an internal diameter less than diameter D_(O) by atleast about 0.5%, and in other embodiments at least about 1%, and in yetother embodiments by at least about 2%. In a preferred embodiment, theinternal diameter of cylinder 552 is less than external diameter D_(O)by about 1%.

[0159] Flange portion 559 of element 556, in preferred embodiments, hasan outer surface 561 extending away from surface 576 of main bodyportion 563 at an angle γ, with respect to the direction of longitudinalaxis 590 of main body portion 563, of between about 1 degree and about11 degrees. Furthermore, in preferred embodiments, flange portion 559has an inner surface 578 extending away from surface 565 of main bodyportion 563 at an angle β, with respect to the direction of longitudinalaxis 590, of between about 15 degrees and about 30 degrees. In preferredembodiments, the absolute value of the difference between angles γ and βvaries from between about 5 degrees and about 20 degrees. In onepreferred embodiment, angle γ is about 8 degrees and angle β is about 20degrees.

[0160] Another aspect of the present invention provides a series ofliquid jet surgical instruments including integrated electrocautery forcauterizing blood vessels or other tissue in a surgical field with anelectric current. The term “integrated electrocautery” as used herein torefer to certain embodiments of surgical instruments provided by theinvention, refers to the inventive surgical liquid jet instrumentsincluding one or more electrodes, preferably located at the distal endof the instrument for placement in the surgical field during operation,which electrodes comprise an integral or attached component of thesurgical instrument, such that electrocautery can be performed with thesurgical instrument without the need for insertion into the surgicalfield of any additional instrumentation, and without the need forremoval and replacement of the surgical instrument from the surgicalfield. Integrated electrocautery capability in certain embodiments ofthe inventive surgical instruments can be configured with a singlepositive electrode located near the distal end of the surgicalinstrument and can be operated in a monopolar mode. For suchembodiments, the electrode provided by the instrument acts as thepositive electrode and the body of a patient acts as a source of groundpotential, for example via contact with a grounding pad in electricalcommunication with an external power supply. A “positive electrode” or“positive terminal” as used herein refers to an electrode or terminal ofa surgical instrument or external power supply having an electricalpotential differing from that of ground potential (0 volts). A “sourceof ground potential” as used herein refers to an electrode, surface,terminal, etc., that is maintained at essentially ground potentialduring performance of electrocautery with a surgical instrument.

[0161] Preferred surgical instruments, according to the invention,including integrated electrocautery further include at least one lumentherein able to conduct an electrically conductive liquid to the distalend of the instrument for insertion into a surgical field. Such a lumenis able to add conductive liquid to the surgical field in order tomaintain an electrocautery electrode at the distal end of the instrumentsubmerged in an electrically conductive liquid so as to enable currentflow from a positive electrocautery electrode to a source of groundpotential within the environment of the surgical field duringelectrocautery. Especially preferred instruments including integratedelectrocautery include a pressure lumen therein able to conduct a highpressure liquid to the distal end of the instrument and able to form aliquid cutting jet within the surgical field. Some preferred surgicalinstruments will also include an exhaust lumen with a jet-receivingopening, positioned opposite a jet opening in a nozzle region of theabove-mentioned pressure lumen, for evacuation of liquid and debris fromthe surgical field. Some preferred embodiments of surgical instrumentsincluding integrated electrocautery can also include a rotatable shafttherein for powering a tissue contacting component, for example agrinding burr. Such an instrument was described previously in thecontext of FIG. 1 and is shown and described, as configured withintegrated electrocautery below in the context of FIGS. 16A and 16B.

[0162] In general, the inventive configurations for providing integratedelectrocautery described below may be utilized in a wide variety ofsurgical instruments capable of delivering a conductive fluid, such asphysiological saline or lactated Ringer's solution, to a surgical fieldof a patient, as would be apparent to those of ordinary skill in theart. In other embodiments, where the distal end of the surgicalinstrument is utilized in surgical fields that are naturally submersedin conductive fluids or are perfused by other means with conductivefluids, the instruments provided by the invention including integratedelectrocautery can lack lumen for delivering conductive fluid to thesurgical field, but may instead comprise, for example, a surgicalinstrument providing only a rotatable shaft that is powered by a liquidjet-driven rotatable rotor positioned within the body of the instrumentand drivingly coupled to the rotatable shaft, such that rotation of theliquid jet-driven rotatable rotor causes a corresponding rotation of therotatable shaft of the instrument as well as rotation of a component atthe distal end of the rotatable shaft, such as a grinding burr, etc.,which is able to perform a desired surgical task within the surgicaloperating field.

[0163] Some preferred embodiments for providing integratedelectrocautery provide surgical instruments having at least twoelectrodes positioned at the distal end of the instrument and within asurgical operating field during operation of the instrument. Suchinstruments can be operated in a bipolar mode, where each of theelectrodes is maintained at a differing electrical potential, such thatthere exist a difference in electrical potential between differentelectrodes of the instrument, tending to drive electrical current alonga conducting path within a surgical operating field from one electrodeto another. In preferred embodiments of instruments configured with atleast two electrodes, at least one of the distal electrodes comprises apositive electrode and at least one other of the distal electrodescomprises a ground potential electrode, such that a complete currentpath between the positive electrode and the ground electrode at thedistal end of the instrument is provided within the surgical fieldduring operation of the instrument.

[0164] As discussed above, integrated electrocautery, as provided by theinvention, may be configured to be utilized with a wide variety ofsurgical instruments both described herein and available in the priorart. For example, a particular embodiment of a deployable liquid jetsurgical cutting instrument previously disclosed and described in detailin commonly owned U.S. patent application Ser. No. 09/313,679 configuredwith the inventive system of integrated electrocautery is describedbelow in the current text of FIGS. 14A-14D. It should be understood thatin addition to the embodiment illustrated in FIGS. 14A-14D, any of theother embodiments of surgical liquid jet cutting instruments describedin U.S. patent application Ser. No. 09/313,679 could be similarlyconfigured with integrated electrocautery as provided by the currentinvention. As described below, in some preferred embodiments, the atleast one integrated electrocautery electrode provided at the distalends of surgical instruments according to the invention comprises atleast a portion of a distal end of a lumen of the surgical instrumentconfigured to either supply liquid to a surgical field (e.g., a pressurelumen) or withdraw liquid from a surgical field (e.g., an evacuationlumen). In some such preferred embodiments, as discussed in more detailbelow, electrodes are provided at the distal end of one or more lumen ofthe surgical instruments by selectively coating the external surface ofsuch lumens with an essentially continuous layer of an electricalinsulator, while leaving certain regions the lumen uncoated, whichuncoated regions providing an electrode surface. An “essentiallycontinuous layer” of electrical insulation as used herein for describingcertain coated regions of conductive lumen or other surfaces of thesurgical instrument according to the invention refers to such surfacesbeing coated with an electrical insulator such that there is essentiallyno, or an acceptably low level of, electrical conduction between thecoated region of the surface and another surface or medium through theelectrically insulating layer at any electrical potentials up to themaximum electrical potential rating of the surgical instrument (about1500 volts for typical electrocautery instruments as described herein).In other embodiments, the electrode(s) may comprise probes or conductiveelements that are separate or separable from the fluid conducting lumenof the instruments.

[0165] An illustrative embodiment for a rotatably deployed surgicalliquid jet instrument is shown in FIGS. 14A-14F. Referring to FIG. 14A,surgical instrument 600 includes a body 602 having a grasping region 604configured to be held within the hand of an operator and an actuatingelement 606 that comprises a slidable sleeve or collar, which is used todeploy the distal end 608 of surgical instrument 600. Slidable sleeve606 is positioned to be easily actuated by a single hand of an operatorof instrument 600. Slidable sleeve 606 can enable the operator to holdbody 602 in at least two different hand/grasping region 604orientations, so that the operator can actuate slidable sleeve 606 whileholding body 602 in either of the at least two hand/grasping region 604orientations. For example, an operator can grip body 602 in a handposition where the thumb of the operator is located near the distal endof gripping region 604. In such position, the operator can actuateslidable sleeve 606 by moving the slidable sleeve with her thumb. In asecond hand/grasping region orientation, the operator can grip body 602,for example, with her thumb positioned toward the proximal end of body602, while actuating slidable sleeve 606 via one or more of the otherfour fingers of her hand.

[0166] Surgical instrument 600 also includes a collar 610 that isrotatably mounted within body 602. Rotatably mounted collar 610 istypically a cylindrically-shaped sleeve, which may be attached to, orform part of, sheath 612. Distal end 608 of surgical instrument 600 isshown in FIG. 14A in an undeployed configuration. Sliding sleeve 606 inthe direction of arrows 614 causes a rotational motion of rotatablymounted collar 610 in the direction shown by arrows 616, which, in turn,causes a rotation of evacuation lumen 618 about a longitudinal axis ofsheath 612, which is essentially parallel to the longitudinal axis ofbody 602 and the longitudinal axis of the portion of evacuation lumen618 within sheath 612. In other embodiments, upon deployment, evacuationlumen 618 may rotate about the longitudinal axis of sheath 612, which isessentially collinear to the longitudinal axis to of the portion ofevacuation lumen 618 within sheath 612, both of which axes areessentially parallel to the longitudinal axis of body 602. In yetalternative embodiments, instead of evacuation lumen 618 rotating upondeployment of instrument 600, evacuation lumen 618 may instead beimmobile with respect to body 602 and pressure lumen 620 may rotate uponactuation of slidable sleeve 606.

[0167] Surgical instrument 600 as shown is also configured withintegrated bipolar electrocautery capability. In the illustratedembodiment, pressure lumen 620 is configured to include a positiveelectrocautery electrode 622 at its distal end, and evacuation lumen 618includes a conductive portion 624 of its outer surface, located withinsurgical field 626 during operation, which act as a ground electrode.Pressure lumen 620 is coated with an essentially continuous layer 626(shaded region) of an electrical insulator along essentially its entirelength, except in a region 622 at its distal end surrounding nozzle 628,which is uncoated and has a conductive surface providing a positiveelectrode. In preferred embodiments, as shown, evacuation lumen 618 isuncoated along its length, except in a region 630 (shaded region) at itsdistal end, which region, surrounding the jet-receiving opening, iscoated with an essentially continuous layer of electrical insulation. Inother embodiments, the roles of pressure lumen 620 and evacuation lumen618 may be reversed so that evacuation lumen 618 is coated along itslength except at its distal end and acts as the positive electrode, andpressure lumen 620 has an outer surface that is conductive along itslength, except at its distal end which is coated, and provides a groundelectrode. In yet other embodiments, both the positive and groundelectrodes may be positioned on the same lumen (i.e. on the pressurelumen or the evacuation lumen). For example, in one such alternativeembodiment, the pressure lumen can be configured as described above(i.e. having an essentially continuous layer of an electrical insulatordisposed along essentially its entire length, except in a region at itsdistal end surrounding the nozzle, which is uncoated and has aconductive surface providing a positive electrode) except also includinga ground electrode disposed along or wrapped around the outer, insulatedsurface of the pressure lumen, where the ground electrode has a distalend that is disposed proximal to the conductive region of the outersurface of the lumen that provides the positive electrode. In such analternative embodiment, the other lumen, which does not provide anelectrode (e.g. the evacuation lumen in the above-describedconfiguration), can be, if desired, constructed from an electricallynon-conductive material, such as plastic.

[0168]FIG. 14A shows the distal end of instrument 600 submersed in anelectrically conductive fluid in a surgical field 626. Pressure lumen620 is coated with insulating layer 626 except at its distal tip. Theuncoated, uninsulated distal tip 622 forms the positive integratedelectrocautery electrode. Evacuation lumen 618, in the illustratedembodiment, is uninsulated except at distal tip 630. In the illustratedembodiment, distal tip 630 of evacuation lumen 618 is insulated in orderto increase the minimum length of the conductive path 632 thatelectrocautery current travels along within surgical field 626 toprevent burning of tissue at the surface of the ground electrode 624 andto reduce any arcing, shorting, or burning of tissue that may be causedby providing a conductive path length that is too short. This can beespecially important when performing electrocautery with surgicalinstrument 600 in an undeployed configuration, as shown, where thedistal ends of pressure lumen 620 and evacuation lumen 618 are in veryclose proximity.

[0169] Upon operation of electrocautery, current will flow fromelectrode 622 and through the target tissue and electrically conductivefluid in surgical field 626 to a conducting surface at ground potential,for example the uninsulated surface 624 of evacuation lumen 618 andsheath 612, which is in electrical communication with lumen 618.Positive electrode 622 and ground electrode surface 624 of evacuationlumen 618 within the surgical field are preferably sized, based on thepower rating of the power supply supplying power to the positiveelectrode, to focus electrical energy at the positive electrode anddisperse the energy at the ground electrode. In typical prior artelectrocautery instruments for performing bipolar electrocautery, thepositive and ground electrodes are of essentially equal size. In suchprior art instruments, essentially all of the tissue located between theelectrodes gets desiccated by electric current during operation of theinstrument. In the inventive configuration, it is preferred that thesurface area of the ground electrode surfaces that are submerged inconductive liquid within surgical field 626 exceed the surface area ofpositive electrode 622 by at least a factor of 2, more preferably by atleast a factor of 5, and most preferably by at least about a factor of10. In all cases, the ground electrode should be sized, with respect tothe size of the positive electrode and the power supplied to thepositive electrode, so that it is large enough to prevent boiling of anyof the liquid contained within surgical field 626, when performingelectrocautery with the instrument. For example, in the embodimentillustrated, positive electrode 622 comprises a positive electrodesurface area of about 0.2 cm², while the insulated surface 630 of thedistal end of evacuation lumen 618 comprises the distal-most about 0.20inch of the lumen, providing a conductive surface 624 of evacuationlumen 618 in surgical field 626 comprising a ground electrode that has asurface area of at least about 2 cm².

[0170] Pressure lumen 620 and evacuation lumen 618, are connected inelectrical communication with positive terminal 632 and ground terminal634 of external power supply 636 respectively. External power supply 636preferably comprises a radio frequency (RF) generator. For embodimentswhere the surgical instrument is configured to provide bipolarelectrocautery, surgical instrument 600 can potentially be used with thebipolar output of essentially any commercially available RF generatorsfor use in electrocautery. Such generator are typically configured tosupply frequencies of between about 500 KHz and about 2 MHz at powersupply levels up to about 80 watts. Positive terminal 632 of powersupply 636 is in electrical communication with body 602 of instrument600 via electrical connector 638 and jack 640. Ground terminal 634 ofpower supply is in electrical communication with body 602 of instrument600 via electrical connector 642 and jack 644. Jack 640 is, in turn, inelectrical communication with pressure lumen 620 within body 602 andjack 644 is, in turn, in electrical communication with evacuation lumen618 within body 602 by connections best illustrated in FIG. 14D anddescribed below. Jacks 640 and 644 and connections 638 and 642 can beany of a wide variety of electrical connection means readily apparent tothose of ordinary skill in the art. In one particular example,electrical connections between body 602 of instrument 600 are madethrough standard “banana” jacks that are mounted to the instrument. Insome preferred embodiments, jacks 640 and 644 are eliminated, andconnectors 638 and 642 are connected directly to pressure lumen 620 andevacuation lumen 618, respectively, within body 602, similar to theconnection of connectors 668 and 669 to the lumen, as described below inthe context of FIG. 14D. In an alternative embodiment, the inventiveelectrocautery instruments can also be operated in a bipolar mode byconnecting the instrument to the monopolar output of a commerciallyavailable monopolar power supply for use in electrocautery. In suchembodiments, pressure lumen 620, providing the positive electrode can beconnected in electrical communication with the positive monopolarterminal of the power supply, while evacuation lumen 618, providing anelectrode at ground potential, can be connected in electricalcommunication with the power supply's grounding connection. Also powersupplied to the instrument from, for example, power supply 636 forperforming electrocautery may, in some embodiments, be user controllablevia a switch or other means provided on power supply 636, body 602, orvia a remote switch, for example a foot operated switch, etc., asapparent to those of ordinary skill in the art.

[0171] In the illustrated embodiment, the pressure and evacuation lumenare constructed from a conductive material, such as stainless steel,that has a relatively low resistance to electrical current flow. Theinsulating coating provided on the outer surfaces of the lumen asdescribed can comprise any insulating coating known to those of ordinaryskill in the art. In one preferred embodiment, the coating comprises apolymeric coating formed on the surfaces of the lumen as shown usingcommercially available shrink-wrap tubing, for example polyvinylidenefluoride (PVDF) shrink wrap tubing. In another embodiment, theinsulating coating comprises a polymeric coating (e.g. PVDF) formed onthe outer surface by a variety of well known coating methods, forexample spray coating, brush coating dip coating, etc. with a variety ofcommercially available polymer layer forming solutions as known in theart. In one preferred embodiment, the insulating layer formed onpressure lumen 620 comprises a polymeric coating formed on the surfaceof the lumen using PVDF shrink-wrap tubing, while the insulating layerformed on the distal end of evacuation lumen 620 is formed by spraycoating with a PVDF layer forming solution.

[0172] The thickness of the electrical insulating layer should be chosento prevent electrical conduction through the layer during operation atmaximum expected operating potentials of the instrument. The thicknesswill depend upon the well known electrical properties of the particulartype of commercially available electrical insulation chosen and can bereadily determined by those of ordinary skill in the art. In oneembodiment, PVDF shrink-wrap tubing having a thickness of between about0.004 inch and about 0.006 inch is used as the electrical coating for aninstrument having a 1,500 volt peak-to-peak rating.

[0173] The distal end of surgical instrument 600 is shown in greaterdetail in FIGS. 14B and 14C. FIGS. 14B and 14C also show sheath 612 androtatably mounted collar 610 in greater detail. Distal end 608 ofsurgical instrument 600 is shown in FIG. 14B in the undeployed positionand in FIG. 14C in the deployed position. In the undeployed position,distal end 608 has a cross-sectional dimension, length, and angularorientation θ with respect to the longitudinal axis of the sheath 612and the longitudinal axis of the body 602 of instrument 600, which areselected to facilitate insertion of distal end 608 into a confinedsurgical operating space, for example a joint capsule, for a particularsurgical procedure. For example, for arthroscopy, at least onecross-sectional dimension of distal end 608, when in the undeployedconfiguration, should be no greater than about 2.8 mm, the length ofdistal end 608 is preferably between 10 and 15 mm, and angle θ ispreferably about 15 degrees. Pressure lumen 620 is fixably mountedwithin body 602, so that it is essentially immobile with respect to body602, and is rotatably mounted within sheath 612 and rotatably mountedcollar 610 so that the sheath can rotate around the outer surface of thepressure lumen upon deployment of distal end 608. By contrast,evacuation lumen 618 is fixably mounted to sheath 612 and/or rotatablymounted collar 610, but is rotatably moveable within body 602 uponrotation of rotatably mounted component 610, so that rotation ofrotatably mounted collar 610 and sheath 612 causes a correspondingrotation of evacuation lumen 618 resulting in deployment of distal end608. Rotatably mounted collar 610 includes a slot or groove 650 having alongitudinal axis 652 that is non-parallel with respect to thelongitudinal axis of rotatably mounted collar 610 and the longitudinalaxis of body 602 of instrument 600. Slot 650 is used to create rotationof rotatably mounted collar 610 upon movement of slidable sleeve 606, asdescribed in more detail below. Rotatably mounted collar 610 alsoincludes a bearing flange 654 which is mounted within body 602 ofinstrument 600 to allow for rotation of collar 610, as described in moredetail below. Deployment of distal end 608, as shown in FIG. 14C,establishes a separation distance l between jet opening 656 in nozzle628 and jet-receiving opening 658 at the distal end of evacuation lumen618. Separation distance e defines a liquid jet path length, when theinstrument is in operation. In certain preferred embodiments, axis 660which defines the direction of a central region of the liquid jetemitted from jet opening 656 when the instrument is in operation, isnon-parallel with respect to the longitudinal axes of sheath 612 andbody 602 of instrument 600. Typically, for such embodiments, axis 660forms an angle with respect to the longitudinal axis of body 602 that isbetween about 45 and 115 degrees, more typically between about 80 andabout 100 degrees, and most typically about 90 degrees.

[0174]FIG. 14D shows a partially cutaway view of surgical instrument 600showing more clearly the proximal end of body 602 and the connection ofpressure lumen 620 to high pressure liquid supply conduit 662 andevacuation lumen 618 to evacuation conduit 664. Pressure lumen 620 canbe connected to high pressure liquid supply conduit 662 via any of awide variety of high pressure tubing connectors 667 well known in theart. Pressure lumen 620 and/or high pressure liquid conduit 662 arefixably mounted within body 602 to prevent movement of pressure lumen620 with respect to body 602 during deployment. Evacuation lumen 618rotates within body 602 upon movement of actuating element 606.Evacuation lumen 618 is connected to evacuation conduit 664, which isflexible and/or twistable within body 602, to allow evacuation lumen 618to rotate.

[0175]FIG. 14D also illustrates one embodiment for providing electricalconnections between pressure lumen 620 and positive jack 640 and betweenevacuation lumen 618 and ground jack 644 within body 602. Positive jack640 is electrically connected to pressure lumen 620 via a wire or otherelectrical connector 668, and ground jack 644 is electrically connectedto evacuation lumen 618 via a wire or other electrical connector 669.Wire/connector 668 is, in turn, crimped to, soldered to, or otherwiseconnected in electrical contact (by any suitable means known to those ofordinary skill in the art) to an electrically conductive surface ofpressure lumen 620 at point 670; likewise, wire/connector 669 is, inturn, crimped to, soldered to, or otherwise connected in electricalcontact to an electrically conductive surface of pressure lumen 618 atpoint 672. Either or both of high pressure conduit 662 and high pressureconnector 667 should be constructed from, or coated with, anelectrically insulating material (e.g. a plastic material) to preventexposure of an operator to electrical shock via contact with the region674 of the high pressure conduit extending outside of body 602.

[0176] The actuating mechanism by which actuating element 606 causesrotation of rotatably mounted collar 610 and sheath 612, in order todeploy distal end 608 of instrument 600, is shown more clearly in FIGS.14E and 14F. Referring to FIG. 14E, a cut away view of actuating element606 is shown. Actuating element 606 can be generally cylindrical inshape and includes two apertures 676 and 678. Aperture 676 is located onthe proximal surface of actuating element 606 and allows actuatingelement 606 to accommodate body 602 of instrument 600. Aperture 678 islocated on the distal surface of actuating element 606 and has acircumference that is nearly equal or slightly greater than the outercircumference of rotatably mounted collar 610, thus allowing rotatablymounted collar 610 to pass through, and rotate within, aperture 678.Bearing flange 654 of rotatably mounted collar 610 is rotatably mountedwithin bearing slots 680 of body 602. Shown in FIG. 14F, actuatingelement 606 includes a pin 682 mounted within aperture 678. As shownmore clearly in FIG. 14E, when assembled, pin 682 fits within slot 650of rotatably mounted collar 610 so that as an operator slides actuatingelement 606 in the direction of arrow 684, pin 682 slides forward inslot 650 causing rotation of rotatably mounted collar 610 in thedirection shown by arrow 686, thus causing deployment of the distal endof instrument 600.

[0177]FIG. 15 illustrates a preferred method, according to theinvention, for forming the nozzle shown above in FIGS. 14A and 14B fordeployable liquid jet instruments having adjustable liquid jet cuttingpath lengths. Such instruments and nozzles are described in greaterdetail in commonly owned U.S. patent application Ser. No. 09/313,679.Step 1 of FIG. 15 entails providing a tubular conduit 700 for use informing a pressure lumen. The tubular conduit is typically formed of abiocompatible metal such as surgical stainless steel and is selected tohave a burst strength sufficient to withstand the contemplated liquidpressures (e.g., a burst strength of at least 50,000 psig).

[0178] Step 2 of the method comprises necking down an end of conduit 700to form a necked region 702 having a reduced cross-sectional area, whichnecked region tapers into a jet nozzle region 704 having an essentiallyconstant internal cross-sectional area. Jet nozzle region 704 terminatesat its distal end in jet opening 706. Necked region 702 can be formed inconduit 700 by a variety of means known in the art, for example byswaging, crimping, or hot-drawing the distal end of conduit 700 to formnecked region 702 and jet nozzle region 704. At the end of Step 2,pressure lumen conduit 700 has an internal radius R, jet nozzle region704 has a minimum internal radius r, and jet nozzle region 704 isessentially co-linear with the axial center line 706 of the tubecomprising the pressure lumen 700 outside of necked region 702.

[0179] Step 3 of the method involves offsetting jet nozzle region 704with respect to tube 700 so that the axial center line 708 of nozzleregion 704 is offset from the axial center line 710 of tube 700 outsideof necked region 702, by a distance D=R-r, so that the jet nozzle region704 and the tubular conduit 700 abut each other along at least one line712 co-linear to an external surface of tubular conduit 700.

[0180] For embodiments where it is desired that at least a centralregion of the liquid jet emitted from jet opening 706 be directed in anorientation that is not parallel with axis 710, jet nozzle region 704may be bent with respect to axis 710 as shown in optional Step 4. Intypical embodiments, nozzle region 704 is bent so that the axial centerline 708 of jet nozzle region 704 forms an angle with respect to axis710 that is between 45 degrees and 115 degrees, more typically betweenabout 80 degrees and 100 degrees, and most typically about 90 degrees.Also preferably nozzle region 704 is bent with respect to tube 700 sothat essentially no portion of jet nozzle region 704 projects radiallybeyond a perimeter that is defined by an outer surface of tube 700outside of necked region 702. In addition to providing a method forforming liquid jet nozzles that have a relatively large length tominimum diameter ratio and that are relatively easy and inexpensive tomanufacture, the inventive method also provides a pressure lumen havinga maximum cross-sectional profile that does not exceed the diameter ofthe tubing comprising the pressure lumen. In addition, the nozzlesformed by the method outlined in FIG. 15 also advantageously provideimproved efficiency for forming a liquid jet as a high pressure liquidstreams through the nozzle. The efficiency of forming the liquid jet isimproved over nozzle designs comprising, for example, a hole bored inthe side of a lumen, due to the fact that necked region 702 provides asmooth tapering flow path for the liquid flowing into nozzle region 704,thus reducing turbulence, recirculating flow patterns, and friction atthe jet nozzle inlet. This effect is known in the fluid mechanical artsas the “vena contracta” effect and can improve fluid flow efficienciesthrough nozzles by as much as 30%.

[0181]FIGS. 16A and 16B illustrate a surgical instrument 1000 includingintegrated bipolar electrocautery that is similar in configuration withsurgical instrument 100 previously shown in FIG. 1 above. The integratedelectrocautery configuration for instrument 1000 is similar to thatdescribed above for instrument 600 of FIGS. 14A-14F, except that forinstrument 1000, which includes a grinding burr 122 located at thedistal end 116 and including a liquid jet-driven rotatable rotor androtatable shaft for rotating the grinding burr, it is preferable toutilize the liquid cutting jet evacuation lumen 120 as the lumenproviding positive electrode 1002 at the distal end of the surgicalinstrument. It is preferred to utilize evacuation lumen 120 as thepositive electrode in surgical instrument 1000 because evacuation lumen120 is connected within body 104 of the instrument to evacuation conduitconnecting block 176 which, in turn, is connected to evacuation conduits178, which extend from the proximal end of the surgical instrument.Evacuation conduit connecting block 176 and conduits 178 are constructedof electrically non-conductive polymeric materials that do not conductelectricity from evacuation lumen 120 to any surface of the instrumentin contact with the user during operation. Conversely, cutting jetpressure lumen 118, which is connected within body 104 in electricalcommunication with ground terminal 1004 of external power supply 1006,is connected via high pressure connector 190 to liquid flow directingvalve 180. The high pressure connector and liquid flow directing valve,as well as high pressure tubing coupler 186 and, in some embodiments,knobs 197, may be constructed of conducting materials and could come incontact with an operator of the device during operation. Thus, it isimportant that such surfaces be maintained at ground potential duringoperation of the electrocautery electrodes of the device.

[0182] External power supply 1006 preferably comprises a radio frequencygenerator as previously described in the context of FIG. 14A above.Positive terminal 1008 of power supply 1006 is in electricalcommunication with evacuation lumen 120 via electrical connector 1010,jack 1012, and electrical connector 1014 within body 104 of theinstrument. Liquid cutting jet pressure lumen 118 is connected inelectrical communication with ground terminal 1004 via electricalconnector 1016, jack 1018, and electrical connector 1020 within body 104of the instrument. Jacks 1012 and 1018 as well as connections 1022 and1024 of the electrical conductors within body 104 to the lumen can beessentially identical to those described above in the context ofsurgical instrument 600 of FIGS. 14A-14F. In some preferred embodiments,jacks 1012 and 1018 are eliminated, and connectors 1016 and 1020 areconnected directly to pressure lumen 118 and evacuation lumen 120,respectively, within body 104. Also, as described above, power suppliedto the instrument from power supply 1006 for performing electrocauterymay, in some embodiments, be user controllable via a switch or othermeans provided on power supply 1006, body 104, or via a remote switch,for example a foot operated switch, etc., as apparent to those ofordinary skill in the art.

[0183] Evacuation lumen 120, in electrical communication with positiveterminal 1008 of external power supply 1006, is preferably insulatedwith an essentially continuous layer 1009 of electrical insulation(shaded region) along its entire length except at distal tip 1002 whichforms a positive electrocautery electrode, as was previously describedabove in the context of pressure lumen 620 of instrument 600. Incontrast to instrument 600 above, and as previously described, insteadof the pressure lumen that forms a liquid cutting jet being configuredto form the positive electrode, in system 1000, it is preferred thatevacuation lumen 120 be so configured. The relative size of theintegrated electrocautery electrodes in surgical instrument 1000 and theelectrically insulating coating used for insulating the lumen of theinstrument are, in preferred embodiments, essentially the same as thatpreviously described for instrument 600 shown in FIGS. 14A-14F.

[0184]FIG. 16B shows the distal end 116 of instrument 1000 submersed inan electrically conductive fluid in a surgical field 1032. Evacuationlumen 120 is coated with electrically insulating layer 1009 except atits distal tip. The uncoated, uninsulated distal tip 1002 forms thepositive integrated electrocautery electrode. Pressure lumen 118, in theillustrated embodiment, is uninsulated except at distal tip 1030. In theillustrated embodiment, distal tip 1030 of pressure lumen 118 isinsulated (shaded region), as previously described above for evacuationlumen 618 of surgical instrument 600, in order to reduce any arcing,shorting, or burning of tissue that may be caused by providing aconductive path length that is too short. Upon operation of theelectrocautery electrode 1002 current flows from electrode 1002 andthrough the target tissue and electrically conductive fluid in surgicalfield 1032 to a conducting surface at ground potential that is inelectrical communication with the ground terminal of the power supply,for example the uninsulated surface 1031 of pressure lumen 118, as wellas other conducting surfaces within surgical field 1032 that are inelectrical communication with the pressure lumen, such as grinding burr122, burr tip support 136, sheath 132, etc. Instrument 1000 could, inalternative embodiments, be connected to a power supply providingmonopolar output for performing electrocautery, as was previouslydescribed for instrument 600. Also, in other embodiments, because thedistal ends of evacuation lumen 120 and pressure lumen 118 aremaintained at an essentially constant separation distance duringoperation of the device, unlike deployable device 606 shown previouslyin FIGS. 14A-14F, insulated tip 1030 of pressure lumen 118 can beeliminated (i.e., the entirety of the external surface of pressure lumen118 may be electrically conductive) without unduly affecting performanceof electrocautery with the instrument.

[0185] The inventive surgical instruments described herein enable theperformance of a number of inventive surgical methods. For example, byutilizing the surgical instruments provided according to the invention,which provide both a liquid cutting jet and a rotatable component at thedistal end of the instrument, surgical procedures may be performedinvolving both liquid jet cutting/ablating and other tasks that utilizeor require rotation of a rotatable component in a surgical field,without the need for exchanging surgical instruments within the surgicalfield or providing multiple instruments to the surgical field. Forexample, the invention enables an operator of such an instrument toinsert the surgical instrument into a surgical field of a patient,create a liquid cutting jet with the surgical instrument to cut orablate a tissue or other material within the surgical field and alsocause rotation of a rotatable component of the same surgical instrumentwithin the surgical field to perform a desired surgical task, forexample contacting the rotatable component with a tissue within thesurgical field (e.g., bone tissue) and grinding, cutting, or ablatingthe tissue with a rotating surface of the rotatable component.

[0186] In some preferred embodiments, a surgical instrument providedaccording to the invention, for example surgical instrument 100 shown inFIG. 1, can be inserted into a surgical field endoscopically, forexample via use of a trocar. In one particularly preferred embodiment,the surgical instruments are utilized within the joint capsule of apatient, for example in the knee or shoulder joint of a patient, forperforming an arthroscopic surgical procedure. Utilizing surgicalinstrument 100, for example, further enables an operator of theinstrument to perform surgical liquid jet cutting/ablating whileevacuating debris and liquid created by the liquid cutting jet from thesurgical field with the surgical instrument without the need forapplying a source of external suction in fluid communication with theliquid cutting jet evacuation lumen of the instrument. Also, asdiscussed above, liquid flow directing valve 180 enables a user ofsurgical instrument 100 to selectively direct high pressure fluid toeither perform liquid jet cutting with the instrument or to utilize theliquid jet-drive rotatable component of the instrument via manipulationof the valve. Alternatively, in some embodiments, the operator can alsodirect high pressure liquid to both create a liquid cutting jet anddrive the liquid jet-drive rotatable component simultaneously in orderto perform both liquid jet cutting and, for example grinding etc. withthe rotatable component, at the same time.

[0187] Furthermore, surgical instruments provided according to theinvention that include integrated electrocautery also permit an operatorof the instrument, in addition to the surgical tasks described above, toapply an electrical signal to an electrode of the same surgicalinstrument used for liquid jet cutting in order to cauterize tissuewithin the surgical field. In some embodiments, electrocautery may beperformed as a separate and distinct step from either liquid jet cuttingor utilization of a rotatable component of the instrument, or, in otherembodiments, electrocautery may be performed simultaneously with theoperation of the liquid cutting jet and/or rotatable componentcapabilities of the instrument. For example, by performingelectrocautery while simultaneously controllably evacuating a portion ofthe liquid from a surgical field with an evacuation lumen of thesurgical instrument, for example by applying suction to a sheathsurrounding the rotatable shaft of the instrument or by operating aliquid cutting jet to create an evacuation via eductor pump action, anoperator with visual access to the surgical field can be able tovisualize a trail of blood (i.e., a blood stream flowing along a streamline from the site of a bleed to the inlet of the source of evacuationprovided by the surgical instrument) and can stop the bleeding with theinstrument before visualization of the entire surgical field iscompromised (i.e., before the entire surgical field is rendered opaquedue to the presence of blood therein). Upon visualizing the trail ofblood during the operation of the instrument, the user can move thesurgical instrument within the surgical field along the trail of bloodtowards the bleeding vessel, while continuously providing evacuation tothe instrument. Upon reaching the site of bleeding, the operator canplace an electrocautery electrode provided on the surgical instrument inproximity to the bleeding vessel and apply an electrical signal to theelectrode to electrocauterize the bleeding vessel to stop the bleedingtherefrom. Such a method is particularly useful for endoscopic surgicalprocedures, for example arthroscopy procedures in the joint capsule of apatient, where the surgical field is visually monitored with anendoscopic camera.

[0188] Those skilled in the art would readily appreciate that allparameters listed herein are meant to be examples and that actualparameters will depend upon the specific application for which themethods and apparatus of the present invention are used. It is,therefore, to be understood that the foregoing embodiments are presentedby way of example only and that, within the scope of the appended claimsand equivalents thereto, the invention may be practiced otherwise thanas specifically described.

What is claimed:
 1. A method comprising: inserting a surgical instrumentinto a surgical field of a patient; creating a liquid jet with thesurgical instrument; driving rotation of a rotatable component of thesurgical instrument with the liquid jet; contacting a rotating surfaceof the rotatable component with a selected tissue of the patient; andgrinding, cutting, or abrading the selected tissue with the rotatingsurface.